Category Archives: Data Corner

Having gone to engineering school, I’ve long loved diving into data sets and excel models. The “Data Corner” series will be my opportunity to focus in on various data sources— e.g., publicly available DOE data and energy-efficient technology market data—and play with different methods of data visualization and statistical analysis.

The Green March Madness Tournament: Setting the 2018 NCAA Tournament Field According to Sustainability

With the Super Bowl in the rearview window and the calendar about to turn to March, the attention of the sports world is about to be completely focused on college basketball and the annual NCAA Basketball Tournament (March Madness). Every year, this 68-team tournament captures the attention of people across the country, whether they are diehard fans or non-sports fans who  are simply participating in the office pool.

Not only does the NCAA Basketball Tournament serve as fodder around the water cooler, with billions of dollars of productivity lost in the American workplace every year, not only in watching the games but also in the various (sometimes unconventional) methods people use to pick the winners in their bracket. You may have seen people choose winners based on which team’s mascot would win in a fight, by choosing the schools with the superior academics, or even by choosing winners based on who has the most attractive head coach (shout out to my alma mater, University of Virginia, that AOL astutely points out would win in this last scenario).

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So with the Selection Committee currently watching the last few games of the regular season as teams try to bolster their chances of making the NCAA Basketball Tournament, I thought I’d take a look at how March Madness would look if the field was selected based on each school’s efforts towards sustainability, energy efficiency, and environmentalism– call it the 2018 Green March Madness Tournament!

This article will take all eligible NCAA schools and create the field of 68 for a tournament, but playing it out won’t be all that interesting because the top seeds will obviously ‘win’ each match up until the Final Four. So keep reading to see the 68 teams that make the tournament and find out which top seed comes out on top– but stay tuned once the NCAA puts out the actual bracket for the NCAA Basketball Tournament because I’ll do a follow-up article and revisit this concept to see who would win each of those real-life matchups based on who rated higher on sustainability!



Metrics used

After extensive research, I found three different measurements and rankings that look at the efforts of colleges and universities across the United States to incorporate sustainable practices, energy-saving measures, and environmentally-friendly practices. The latest version of the data for these measures, which are explained in detail below, were pulled to serve as the metrics of who would participate in the 2018 Green March Madness Tournament.

The Sustainability Tracking, Assessment & Rating System

The Association for the Advancement of Sustainability in Higher Education (AASHE) uses its Sustainability Tracking, Assessment & Rating System (STARS) to measure how successfully institutions have been performing in sustainability matters. The mission statement of STARS details how it “is intended to engage and recognize the full spectrum of colleges and universities- from community colleges to research universities- and encompasses long-term sustainability goals for already high-achieving institutions as well as entry points of recognition for institutions that are taking first steps towards sustainability.”

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STARS is completely voluntary, transparent, and based on self reporting. Dozens of different metrics are included in the STARS measurements, including in the categories of curriculum (e.g., whether the institution offers sustainability-focused degree programs), campus engagement (e.g., whether sustainability-related outreach campaigns are held on campus), energy use (e.g., availability of clean and renewable energy sources on campus), transportation (e.g., inclusion of alternative fuel or hybrid electric vehicles in the institution’s fleet), and many more that are found in the credit checklist.

Based on performance based on these metrics, each school can earn up to 100 points and a corresponding rating of STARS Reporter, STARS Bronze, STARS Silver, STARS Gold, or STARS Platinum. Because STARS is self-reported, institutions can continually make improvements and resubmit for a higher score. However for the sake of this Green March Madness Tournament, the latest scores for all schools playing Division I NCAA basketball were pulled as of the beginning of February 2018, with any schools not participating in the STARS program receiving a score of zero.

The Cool Schools Ranking

The Sierra Club publishes an annual ranking called the Cool Schools Ranking to measure which schools are doing the most towards the Sierra Club’s broader sustainability priorities. The data for the Cool Schools Ranking largely comes from the STARS submissions as well, though with some key changes— the Sierra Club identifies the 62 questions of the STARS survey that they consider the most crucial to their definition of sustainability and put that data in a custom-built formula, they only use information submitted or updated to STARS within the past year, and they asked institutions to also detail what moves they have made to divest their endowment from fossil fuel companies (a question not asked by STARS).

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As with STARS, participation in the Sierra Club’s rankings is completely voluntary and transparent, ultimately resulting in a numeric value on the 1000-point scale to use for the rankings.  For the scoring towards the Green March Madness Tournament, all eligible teams had their Cool Schools Ranking score pulled and divided by 10 (so it would be on a 100-point scale like the STARS rating), while schools that were not included in the ranking were given a score of zero.

SaveOnEnergy Green Score

The last of the three rating systems used for the Green March Madness Tournament is the 2017 Green Score given by SaveOnEnergy.com. The goal of this scoring system is to give credit to institutions making “noteworthy progress in eco-friendliness and sustainability.” The SaveOnEnergy Green Score takes the top 100 schools in the U.S. News & World Report and awards them scores based on their Princeton Review Green Score, as well as state data on farmers markets, local public transportation options and walkability scores, density of parks in the area of the school, state data on clean and renewable energy options, and availability of green jobs.

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The data for the SaveOnEnergy Green Score is a mix of voluntary data (e.g., data submitted to the Princeton Review Green Score) and mandatory statistics (e.g., state data on energy options and green jobs). In the end, SaveOnEnergy takes all of these factors to create a final score out of 100– though the score is only published for the top 25 schools, and the remaining schools are ranked without their score displayed. To account for this, a best-fit equation was used to correlate ranking with the score of the top 25 schools and extrapolated that equation to determine a score for the remaining ranked schools. Schools that did not make the SaveOnEnergy Green Score list were given a score of zero.

Final Green March Madness Tournament score

In the end, all 351 schools that participate in Division I basketball (representing 32 different athletic conferences) were given a final score that was the average of the STARS score, the Cool Schools Ranking score divided by 10, and the SaveOnEnergy Green Score, so that the final score is also on a 100-point scale (the final scores for all schools can be found in this article’s accompanying Google Spreadsheet).

Before moving forward, let’s make clear that this ranking system is mostly just for an overview of sustainability scores among schools based on publicly available data, and it should by no means be considered comprehensive. Indeed, each of the three ranking systems make clear that there are many more schools that care about energy and the environment and are also making great strides that do not appear on these lists. These schools might not have the time or resources to submit their data, the submission of the data to these third parties was not a priority, or they simply weren’t included on the U.S. News & World Report Top 100 Universities list and so their data was not included in the SaveOnEnergy Green Score list.

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That being said, schools that take the time to report their sustainability are showing that doing so is a priority to them and demonstrating a commitment to the cause that should be applauded and recognized. While there are many schools that didn’t report their data that are certainly still environmentally friendly (indeed, about half of the schools in Division I basketball ended up with a score of zero for not appearing in any of the three lists, but it would be foolish to believe that none of those 178 schools are working towards energy efficiency and sustainability), the submission of data can be considered a sign that transparency regarding sustainability is important to those in charge and thus the reporting schools earn a well-deserved place in the Green March Madness Tournament scoring. For that reason, the rest of this article will unapologetically use the Green March Madness Tournament Score as the definitive factor to determine sustainability rankings of the schools.

Quick facts and figures

Before moving on to selecting which teams made the prestigious Green March Madness Tournament, let’s take a look at a few quick facts from the scoring:

  • 173 out of 351 teams registered a score greater than zero on the Green March Madness Tournament Score, meaning over 100 schools who registered a non-zero score will still find themselves on the outside looking in.
  • Even rarer, though, are teams that have scores in all three scoring metrics used. Only 33 teams have a non-zero score in all three metrics, while only 112 teams have a non-zero score in two or more metrics.
  • As shown below in the table of conferences and conference champions, the highest score went to American University of the Patriot League with 73.4, while the lowest non-zero score went to South Dakota State of the Summit League with 9.2.
  • Looking at each of the 32 conferences:
    • 4 conferences (Pacific-12, Big Ten, Ivy League, and Atlantic Coast) had 100% of their teams score greater than zero.
    • 2 conferences (Atlantic Sun and Northeast) had only a single team score greater than zero, thus making the crowning of a conference champion rather easy.
    • 5 conferences (Big South, Metro Atlantic Athletic, Mid-Eastern Athletic, Southland, and Southwestern Athletic) didn’t have any teams score greater than zero.

Selecting the field

Even though this is mostly a silly exercise, I still wanted to follow the protocol of the real NCAA Basketball Tournament Selection Committee when determining who should make this ‘Big Green Dance’ (and, in doing so, gained some respect for the massive amount of puzzle pieces they must juggle!). The process is famously intense, with 10 committee members spending countless hours keeping up with the college basketball landscape during the year, only to convene for a five-day selection process that requires hundreds of secret ballots.

The entire process is very detailed, but it can be boiled down as follows:

  1. All 32 conference champions receive an automatic bid into the tournament
  2. The next best 36 teams are then chosen as ‘at-large bids’ to bring the total field to 68 teams
  3. All 68 teams are ranked from top to bottom, regardless of their status as a conference champion
  4. The top four teams are ranked as number one seeds in each of the four regions, then the next four are two seeds, the next four are three seeds, etc.
  5. While placing teams into each region, care is taken to ensure that each of the four regions is fairly equally balanced and that teams that played each other during the season are prevented from  having a rematch in the tournament until the later rounds (teams can be bumped up/down by a seed or two to assist in these requirements)
  6. The last four teams to make the tournament in at-large bids and the last four teams to make the field altogether are paired off to compete in the First Four games, with the winners advancing to the remaining field of 64.

While the criteria used to rank teams for the Selection Committee include resources such as the Rating Percentage Index (RPI), evaluations of quality wins based on where the game took place and how good the opponent was, and various computer metrics, things are easier in the Green March Madness Tournament Selection Committee as we only need to use the single number result of the Green March Madness Tournament Score.

The 68-team field

The bracket

For the full suite of teams, conferences, and scores, refer to the accompanying Google Spreadsheet of final figures. Using these numbers and sticking to the above selection guidelines as much as possible, the following bracket is the official result for the 2018 Green March Madness Tournament Bracket:

Click to enlarge

Breaking it down by each region for ease of reading:

The East region

The West region

The Midwest region

The South region

Note that the five conferences that didn’t produce a single team with a non-zero score would still get the automatic bids for their conference champion (four as play-in teams for the First Four and one more as a 16 seed without a play-in game), so perhaps they’ll draw straws to see who gets to go into the tournament. Regardless, they are in the bracket and labeled as that conference’s champion (placed in no particular order), just waiting to be beaten soundly by their respective sustainable opponents.

Analysis of the field

In terms of conferences, we see big winners come from the Pacific-12 (8 tournament teams) and the Big Ten (7 tournament teams), but in third is the surprise conference of the Ivy League (6 tournament teams) who is rarely in the conversation for getting more than a single team in the NCAA Basketball Tournament. On the other end of the surprises, the Big East and the Southeastern Conference (both major conferences that typically nab a handful of bids each) were kept to only one team each in the tournament.

For individual teams, we find some other surprises. A number of perennial stalwarts of the college basketball scene find themselves in the unfamiliar position of being on the outside looking in– 7 out of the 10 teams with the most NCAA Tournament appearances failed to receive a Green March Madness Tournament big (Kentucky, Kansas, UCLA, Louisville, Duke, Notre Dame, and Syracuse). On the other side of the coin, five teams (Denver, New Hampshire, William & Mary, UC Riverside, and Bryant University) that have never made the NCAA Tournament have finally found success with the Green March Madness Tournament.

Another common exercise leading up to the announcement of the NCAA Basketball Tournament teams is looking at the bubble teams, those that are just on the edge of making the tournament but find themselves potentially falling just short.  The most painfully close bubble teams for the 2018 Green March Madness Tournament were the five teams that fell less than one point shy of an at-large bid: Louisville, Northern Arizona, Ohio State, IUPUI, and Arkansas. Most painful was Louisville who fell just 0.12 points shy of being the last team in (though maybe it was serendipity– who knows if Louisville would have had to vacate that appearance, too).

What did the top performing schools have in common?

Looking at the teams that scored particularly high and scored the best seeds in the Green March Madness Tournament, a couple of trends appear:

  • Sustainability-focused schools: It’s worth noting that every team that was ranked in all three metrics ended up with a good enough score to make the tournament. As previously noted, such commitment to ensuring data is delivered for all three metrics shows the cause of sustainability is a priority and these schools are naturally rewarded by being guaranteed to make the Green March Madness Tournament.
  • City schools: A common theme found in the upper half of the schools that made the Green March Madness Tournament is that the are located in or near major U.S. cities (including one seeds American University and George Washington, three seed Northwestern, four seed Columbia, six seed Boston University, seven seed Denver, and eight seed Miami (FL)). The reason an urban setting might help schools score well in these rankings is because cities are more likely to have local sustainability organizations to partner with the school, access to effective public transportation, high walkability scores, and other nearby resources from the community that can be used for the school as well. Each of these factors positively effects the ratings that go into the Final Green March Madness Tournament Scores.
  • Green states:  Outside of the city in which a school is located, the state a school is in (and the state’s relative ‘green-ness’) has significant impact. The top of the tournament seeding is populated with teams from states often considered particularly green by various metrics. For example, the annual state scorecard rankings from the American Council for an Energy-Efficient Economy (ACEEE)  shows heavy representation from the top five states in the ACEEE scorecard in the Green March Madness Tournament: Massachusetts (Boston University, Harvard, Massachusetts), California (UC Santa Barbara, Santa Clara, UC Riverside, San Jose State, UC Irvine, Cal State Northridge, California, San Diego), Rhode Island (Brown, Bryant University), Vermont (Vermont), and Oregon (Oregon State, Portland State, Oregon, Pacific). Together, those five states account for over a quarter of the teams that made the Green March Madness Tournament, reflecting the benefits to institutions in states that commit to green jobs, renewable energy development, and other sustainability initiatives.

The National Champion

The downside of filling out our bracket based on the Green March Madness Tournament Scores is that by continuing through with the tournament, we won’t find any upsets and the top seeds will always win (again, we’ll revisit once the real NCAA Basketball Tournament bracket is released to see which of those teams would win based on sustainability). In the end, our Final Four is made up of all one seeds, as shown below, with the final champion being…

Drumroll…

 

American University! In the three times appearing in the NCAA Basketball Tournament, the Eagles have gone winless– but once the Green March Madness Tournament comes along they go all the way! Congratulations to them, and best of luck to all schools in the ‘real’ tournament in March, to all schools looking to improve their sustainability scores before next year’s Green March Madness Tournament, and to all of you in finding the best way to fill out the brackets for you office pool this year!

Sources and additional reading

Cool Schools 2017 Full Ranking: Sierra Club

March Madness bracket: How the 68 teams are selected for the Division I Men’s Basketball Tournament: NCAA

SaveOnEnergy 2017 Green Report: Top Universities in the U.S.: SaveOnEnergy

The Sustainable Tracking, Assessment & Rating System: Association for the Advancement of Sustainability in Higher Education

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

About That Tesla Roadster Flying Through Space– What Kind of Gas Mileage Is It Getting?

Elon Musk and his SpaceX team made huge news last week when they successfully completed the maiden launch of the Falcon Heavy on the afternoon of February 6, 2018. This launch was such a monumental accomplishment because the private company venture (the heaviest commercial rocket ever launched) could one day be used to take astronauts to the Moon and Mars, and it demonstrated the ability to do so with the ability to guide the rocket boosters back to Earth for reuse.

While all of this news was one of the most amazing accomplishments by a private sector company in terms of scale and implications for humanity, one of the most gripping aspects of the project ended up being the fact that the test payload Musk chose to attach to the rocket was his personal Tesla Roadster, painted cherry red to represent the launch’s step towards getting to Mars. The reason behind launching this $100,000 car into space (never to return) was purely to capture people’s attention and imagination, a goal that was undeniably achieved as Musk was able to give the world this image that mindbogglingly is real and not using any sort of Photoshop and was compelling enough to get everyone to take notice of this amazing accomplishment.

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Given that the mission statement of Tesla is “to accelerate the advent of sustainable transport by bringing compelling mass market electric cars to market as soon as possible,” I found it cheekily ironic that fossil fuel– rocket fuel, no less– had to be used to get this Tesla mobile. This not entirely serious thinking led me to the tongue-in-cheek line of questioning– how did the fuel economy of this space-bound Tesla compare with the fuel economies of cars that are restricted to a terrestrial existence? What about the relative carbon dioxide (CO2) emissions?

Let’s bust out that handy back-of-the-envelope to scratch out some (very) approximate estimates!



The Tesla Roadster

The car that was sent into an elliptical orbit around the Sun was Elon Musk’s personal 2008 Tesla Roadster, ‘piloted’ by a mannequin in a SpaceX flight suit named Starman. This model of Tesla electric cars weighs in at 2,723 pounds, went for a base price of $98,000, sold 2,400 units before production was stopped, and was notable as the first highway legal serial production all-electric car using lithium-ion batteries and the first all-electric car to travel more than 200 miles per charge.

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Fuel Economy

The official fuel economy rating of the Tesla Roadster from the Environmental Protection Agency (EPA) is 119 miles per gallon equivalent (MPGe), being able to travel 245 miles on an eight-hour charge (the MPGe value compares the amount of electricity needed to move an electric car with the amount of gasoline needed to move a gasoline-powered car using the energy equivalence of one gallon of gas matching 33.7 kilowatt-hours of electricity).

As a comparison for the fuel economy of a Tesla Roadster:

The following table summarizes this range of fuel economies of the Earth-restricted vehicles:

Carbon dioxide emissions

While the use of electricity when driving a Tesla (or any electric car) is indeed carbon neutral in that no CO2 is being emitted from a tailpipe, it is not entirely true to rate the CO2 emissions per mile driven as zero. The simple reason behind that is that the generation of electricity that ends up in the vehicles come tied to the CO2 emissions at the electric power generation plants. While the portion of the U.S. power sector that is driven by carbon neutral sources like wind, solar, and nuclear is growing, fossil fuels like coal, natural gas, and petroleum still accounted for over 60% of U.S. electricity generation in 2017. As such, whenever a Tesla gets plugged into the grid it is likely receiving electricity that comes from CO2-emitting sources (not to mention the inefficiencies that come from the transmission & distribution of the electricity, the charging losses of the batteries, and the ‘vampire losses’ of charge when the car is not plugged in and not in use). Because of this, the CO2 footprint of driving a Tesla, or any electric vehicle, is intrinsically tied with the energy makeup of the particular electricity supplier.

The Nissan Leaf, another all-electric vehicle, accounts for about 200 grams of CO2 per mile (g CO2/mile) on average across the United States, while California (with one of the highest proportions of clean electricity in the country) comes in at 100 g CO2/mile and Minnesota (a state that is very dependent on fossil fuel) comes in at 300 g CO2/mile. For the sake of this exercise we’ll use these readily available Nissan Leaf numbers as the benchmark CO2 emissions per mile of an electric car, even though the Tesla Roadster is likely slightly different due to different charging rates and battery technologies.

As a comparison for this rate of CO2 emissions of an electric car:

The following table summarizes this range of CO2 emissions for non-rocket fueled vehicles:

Launching Starman’s Roadster

At pre-launch, Musk noted that ultimately the payload (i.e., Starman’s Tesla Roadster) would get 400,000 million kilometers (almost 250,000 million miles) away from Earth, traveling at 11 kilometers per second (almost 7 miles per second), and would orbit for hundreds of millions, or even billions of years (see below graphic of the initial orbit that Musk tweeted out after the launch). To accomplish this, the Falcon Heavy generated 5 million pounds of thrust at liftoff (making it the most powerful liftoff since Nasa’s Saturn V). Generating this amount of power is no small feat.

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To estimate exactly how much fuel was used (and how much that would be in the equivalent gallons of motor gasoline) requires some estimates, but we have enough information to get at least in the ballpark.

When fueling its rockets, SpaceX uses a highly refined type of kerosene (also known as RP-1) because of its high energy per gallon, in addition to liquid oxygen (LOX) needed for combustion (the amount of LOX required is about double the amount of RP-1). The first stage of a Falcon 9 rocket (another type of rocket used by SpaceX) uses 119,100 kilograms (kg) of RP-1 and 276,600 kg of LOX, while the second stage uses 27,850 kg of RP-1 and 64,820 kg of LOX (see graphic below for what that multi-stage launch sequence looks like). A simplified explanation of the Falcon Heavy is really that it’s composed of three Falcon 9 rockets merged into the first stage and the second stage consisting of disconnecting from the three Falcon 9 rockets and a single stage 2 rocket (along with the payload) continuing on. Making rough estimates, this means the Falcon Heavy required three times the fuel of the first stage and one times to fuel of the second stage of the Falcon 9, or a total of 385,150 kg of RP-1 and 894,620 kg of LOX (this is admittedly a simplification of the fueling process, but I’m also admittedly not a rocket scientist. In attempting to keep these estimates as rigorous as possible, see the citations and links contained here and let me know in the comments if I got something wrong– particularly if you are a rocket scientist!).

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Musk, when discussing the potential dangers of the Falcon Heavy launch, noted that the fuel on board was 4 million pounds of TNT equivalent. In fact, the energy contained within looks like it could be over double that (whether this is a sign of Musk simplifying for the sake of giving the press a quote, speaking approximately without reference to the exact calculations beforehand, or missteps in my calculations, I’ll let you decide). While the total weight of the LOX is over double the weight of the RP-1, the LOX is simply there to allow for combustion and maximize the efficiency with which the rocket is burned. As such, the energy density of RP-1 is what we care about. Using an energy density of 43.2 Megajoules (MJ) per kg, we find that the energy contained in the Falcon Heavy’s fuel tanks was over 16.6 million MJ, which is equal to about 126,000 gallons of gasoline equivalent (or over 8.7 million pounds of TNT— so while our estimate is over double Musk’s offhand remark, we can take solace that we’re in the same order of magnitude!).

In terms of the CO2 released by burning this much fuel, we can use the “well to wake” emissions number of RP-1 of 85 grams of CO2-equivalent per MJ to estimate that the total CO2 emissions were over 1.4 million kg (or 1,400 metric tons) of CO2.

Comparing Starman’s Tesla with Earth vehicles

First things first– that’s definitely the most fossil fuel used and CO2 emitted ever in getting a car from point A to point B. But that doesn’t necessarily mean that Starman’s Tesla is the least efficient or most harmful to the environment. That’s because once the fuel is burned and Starman’s Tesla  was set into orbit in perpetual motion, logging millions of miles on the odometer while traveling 25,000 miles per hour, the rest of its journey was all without additional energy input.  Even the camera and communication equipment on board were attached to a battery with 12 hours of life with no other sources of energy, so after the 12 hours the equipment went dark and there was no more energy input to Starman’s Tesla– just momentum and gravity working their magic. So despite this initial abundance of fossil fuel and related CO2 emissions to set the Tesla in motion, on a per mile basis (which is how fuel economy and emissions are calculated) it will inevitably becomes the most efficient and clean car of all time!

But how long will it take for this to be true?

Fuel economy

In terms of fuel economy, the MPGe of Starman’s Tesla improves linearly with every mile traversed through space. After 1,200 miles, the Falcon Heavy and its payload of Starman and his Tesla left Low Earth Orbit, but the massive amount of fuel means it barely even registers as a blip on this graph at about 0.0095 MPGe.

After two days when Starman’s Tesla had traveled 450,000 miles, the fuel economy had risen to a little less than half that of the freight truck. You can also note in the graph that at the point of the 36,000 mile warranty of the Tesla Roadster the fuel economy aws still less than 0.3 MPGe– you’d certainly have a lot of angry Tesla owners if that’s all they were able to recoup on gasoline costs by the end of their warranty!

Lastly, after teasing out how far Starman’s Tesla would have to travel to become the most fuel efficient car (that is or ever was) on Earth, we find that it would take:

  • About 900,000 miles to beat the fuel economy of freight trucks;
  • About 2.9 million miles to beat the average of the U.S. light-duty stock fuel economy;
  • About 3.7 million miles to meet the 2018 light truck standards;
  • About 5.0 million miles to meet the 2018 car standards;
  • About 7.3 million miles to meet the most efficient gas powered car available;
  • About 15 million miles to meet the efficiency of an Earthly Tesla Roadster; and
  • About 17.2 million miles traveled to equal the 136 MPGe of the Hyundai Ioniq Electric, the most efficient car available.

As previously mentioned, the equipment on board Starman’s Tesla was attached to a battery that only had 12 hours of life, after which there was no functioning equipment on the Roadster. As such, there is no inherent tracking or communicating with Starman’s vehicle as it continues on its journey, making its exact tracking through space difficult.

But fear not– a great tool was launched after the Roadster was launched into orbit called ‘Where is Roadster?‘ Using the knowledge available regarding the position, orbit, and speed of the Tesla, this tool shows approximately where in its orbit the Roadster is and how far it has traveled in aggregate. This tool does not allow going back to see when exactly certain distances were passed, but from watching the site myself I can attest that Starman’s Roadster passed 17.2 million miles on the afternoon of February 14, 2018– meaning it only took eight days for this Tesla Roadster to become the most efficient car ever! Any distance it continues to travel will only increase the overall fuel economy (if you want to calculate this for yourself at any given moment, divide the current miles from ‘Where is Roadster?‘ by 126,279 gallons of gasoline equivalent).

CO2 emissions

In terms of CO2 emissions per mile, Starman’s Tesla improves according to a power equation– meaning in this case that there are drastic improvements in CO2 emissions per mile initially that flatten out over time. By the time Starman’s Tesla leaves Low Earth Orbit, not nearly enough miles have been traveled to offset the massive amount of CO2 emissions from the rocket launch, with Starman’s Tesla coming in at a mindblowing 1.2 million g CO2/mile at 1,200 miles– the equivalent of 182 freight trucks moving a mile at a time.

After two days and 450,000 miles traveled, the CO2 emissions per mile had dropped to 3,143 g CO2/mile, blowing way past the average freight truck emissions after about 219,000 miles. After the 36,000 mile warranty, the emissions still averaged over 39,000 g CO2/mile– another tidbit that would enrage an environmentally conscious electric car owner if it happened to them.

Again projecting out how far Starman’s Tesla would have to travel to become the cleanest car in existence, we find that it would take:

  • About 3.4 million miles to be cleaner than the average passenger vehicle;
  • About 4.7 million miles to be cleaner than an electric vehicle charged in fossil-fuel-dependent Minnesota;
  • About 5.0 million miles to meet the emissions standards for light trucks in 2018;
  • About 7.0 million miles to meet the emissions standards for cars in 2018;
  • About 7.1 million miles to be cleaner than the average electric vehicle in the United States; and
  • About 14.1 million miles to be cleaner than an electric vehicle charged in renewable-energy-heavy California.

Again by watching the ‘Where is the Roadster?‘ tool, I found that Starman’s Tesla also became the cleanest car ever (on a g CO2/mile basis) on February 14, only 8 days after launch. As with the fuel economy, this figure will only get better and better as Starman racks up the limitless miles circling the Sun for millions or billions of years (to calculate an updated emissions per mile, divide 1,414,270,800 grams of CO2 emissions by the updated miles traveled from ‘Where is Roadster?‘).

Conclusion

So there you have it, despite the massive amounts of fuel and resultant CO2 emissions required to launch the Tesla Roadster in space, it only took eight days of traveling faster than any car ever before to become the most fuel efficient and least CO2-emitting (on a per mile basis) ever made. But that fact was inevitable given that it’s in orbit around the Sun and will likely be for the rest of humanity’s existence– so what really is the point of crunching the numbers like this? Hopefully you’ll come away from this article with a handful of takeaways and topics/issues on which to do some more reading and learning:

  1. The impressiveness of this feat accomplished by Musk adn the whole team at SpaceX cannot be overstated. The Tesla Roadster weighs just 2,723 pounds, but this launch was testing a rocket system whose ultimate payload capacity extends to almost 141,000 pounds sent to Low Earth Orbit, 37,000 pounds sent to Mars, and 7,700 pounds sent to Pluto– all at decreased cost compared with historical launches that really opens up doors. That is the most important takeaway from the Falcon Heavy launch, a huge step towards what Musk hopes to be the next great space race.
  2. Beyond that, running through these tongue-in-cheek calculations should hopefully serve to pique your interest and give some information on the relative fuel efficiency electric cars are able to achieve, but also some of the current shortcomings in terms of using them as a way to reduce CO2 emissions. A lot of interesting pieces have been written on the true environmental impact of electric cars, as well as how that might evolve in the future. I’ll recommend a couple (from Green Car Reports, Wired, The Union of Concerned Scientists, and Scientific American, just to name a few), but it’s an important topic with much more out there to be read and debated.
  3. In addition, given the relative fuel economies and CO2 emissions of various vehicles (as wella s regulations covering these measurements), let that be a reason to look more into the efficiencies and emissions of your vehicles. In particular, you’ll note the average passenger vehicle has twice the emissions per mile as a new Model Year 2018 car that complies with EPA regulations, while the new cars will also get up to 74% more MPG compared with the average for the U.S. fleet of light-duty vehicles. Keep these types of figures in mind the next time you’re in the market for a vehicle, and consider how much fuel and emissions savings are being protected and increased by these existing regulations (both fuel economy and car emissions regulations are being considered for rollbacks by the Trump administration) as automotive regulations and policies continue to make the news.

Sources and additional reading

Can Driving a Tesla Offset the Impact Of A SpaceX Launch? Clean Technica

Electric Cars Are Not Necessarily Clean: Scientific American

Elon Musk says SpaceX has ‘done everything you can think of’ to prepare Falcon Heavy for launch today: Business Insider

Falcon 9 v1.1 & F9R Launch Vehicle Overview: Spaceflight 101

Falcon Heavy: SpaceX

Falcon Heavy: SpaceX stages an amazing launch — but what about the environmental impact? The Conversation

How Much Fuel Does It Take To Get To The Moon? Huffington Post

Musk’s Falcon Heavy Packs a Huge Payload: Forbes

SpaceX’s Falcon Heavy Rocket: By the Numbers: Space.com

SpaceX’s Falcon Heavy rocket nails its maiden test flight: NBC News

SpaceX launch: Why is there a Starman spacesuit in the Tesla Roadster? Express

The Falcon Heavy Packs A Huge Payload: Statista

Where is Elon Musk’s Tesla Roadster with Starman?

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Super Bowl Sunday and Electricity Demand: What Happens in Cities with Super Bowl Teams and Host Cities?

The Super Bowl is upon us once again, along with all the fun sideshows that go with it. There are few events in American culture that bring as many people collectively around a single event quite like the Super Bowl, with even non-football fans gorging on fatty foods, enjoying the commercials, and relishing in the excuse to attend parties on a Sunday evening. The grip that Super Bowl Sunday has on our group consciousness allows for some interesting analysis of data (how much food do we collectively eat?) and myths (despite what I heard on the schoolyard growing up, the simultaneous flushing of toilets during halftime has not actually caused damage to sewer systems).

Thinking of the ‘everyone flushing the toilet at the same time’ myth got me to wondering about how electricity demand as a whole is affected by the Super Bowl, particularly in the regions whose teams made the big game (and presumably cause even more of the population to tune it) and the region hosting the Super Bowl. Indeed, grid operators like ISO New England recognize that ‘even when the game is thousands of miles away, the Super Bowl can have a big impact on regional electricity demand with spikes and dips throughout the game,’ requiring them to monitor the demand closely throughout the day.

So just as I started this football season analyzing the sustainability-ranking of each team, I’ll end it by analyzing the championship game in energy terms. Going into this analysis, I expected that a city/region having their team in the Super Bowl, or hosting the festivities, would lead to a definitive increase in power demand– but keep reading to see why I was surprised to find that assumption was misguided.



Graphical Results

We’ll jump right into the graphical results of this analysis– if you’re interested in reading the methodology, head down to the Methodology section now. The methodology section will also answer where the data came from and why for Super Bowls from 2015 and earlier there isn’t data available for each of the three relevant cities (two participant teams and the host city).

Super Bowl 51

Starting with the most recent Super Bowl and working backwards, first up is Super Bowl 51. This game saw the New England Patriots defeat the Atlanta Falcons in Houston, Texas, in the largest comeback in Super Bowl history. Below is the graph of electricity use in the power regions that are home to Boston, Atlanta, and Houston compared with a typical Sunday of comparable weather (note that all times displayed in this and other graphs are in Eastern Standard Time even when the region in question is in a different timezone):

For this specific Super Bowl, the electricity demand in all three regions is mostly lower than a normal Sunday for the whole day, though the demand of the Atlanta fans drops even lower than normal come game time and we see the New England electricity demand increase compared with normal as the games continues. As will be discussed later, this difference in how the two cities reacted over the course of the game likely reflects the attitudes and activities each fan-base had to what was looking like a blowout victory for Atlanta.

Super Bowl 50

Super Bowl 50 featured the Denver Broncos defeating the Carolina Panthers in Santa Clara, California. Comparing the electricity use this Super Bowl Sunday with a typical winter Sunday in the power regions that contain Denver, Charlotte, and Santa Clara gives the following visual:

In what we’ll find is a more typical effect of Super Bowl Sunday, the electricity use in both Denver and Santa Clara saw an increase from normal use early in the day, only to fall below average during the time when the game was on. Panthers fans, however, set an unparalleled increase in power demand compared with a normal Sunday all day, but especially high during the afternoon lead up to the game and notably dropping during the game.

Super Bowl 49

Working backwards, Super Bowl 49 is the first instance where we find that data is not available for all three regions (see Methodology section for an explanation). In this game, which found the New England Patriots defeating the Seattle Seahawks in Glendale, AZ on a game-ending interception in the end zone, we only have data from the New England power region to consider:

In looking at the New England electricity demand, we find a peak compared with normal early in the day and a general increase compared with normal over the course of the game.

Super Bowl 48

For Super Bowl 48, where the Seattle Seahawks dominated the Denver Broncos all game in East Rutherford, NJ, the only available data was for the power system that is home to East Rutherford.

Here we again find a peak in electricity demand compared with normal early in the day, which dissipates and eventually leads to lower electricity used during the actual playing of the Super Bowl compared with a normal day.

Super Bowl 47

Last but not least is Super Bowl 47, featuring the Baltimore Ravens defeating the San Francisco 49ers in New Orleans, LA. I was particularly looking forward to gathering the data from this one (and was disappointed to find only the Baltimore area data available) because this is the game that infamously featured a power outage in the stadium that delayed the game by over half an hour. I was hoping specifically for the New Orleans data to see what the electricity demand looked like before and after the blackout, but it was not meant to be.

However we can see from the Baltimore data a peak in electricity use compared with normal early in the day and a distinct drop off as the game is set to begin and throughout the course of the game. Because the data provided is hourly, it’s not clear if there was any effect during the half hour delay in the Super Bowl, but it looks like people in Baltimore continued whatever it was they were doing during the power outage in New Orleans, rather than decide to use the break in action to start up the dishwasher or the clothes dryer.

Conclusions

General trends

Interestingly, we don’t find one iron-clad trend that weaves its way through the entire data set analyzed, though there are some patterns.

  • For regions with teams in the Super Bowl, four out of six (Baltimore in 2013, New England in 2015, Denver in 2016, and Carolina in 2016) of them show an increase in electricity use during the lead up to the game, while four out of six (Baltimore in 2013, Denver in 2016, New England in 2017, Atlanta in 2017)  of them show a decrease in electricity use during the game.
  • For the regions hosting the Super Bowl, a similar trend is found. Two out of three host regions (East Rutherford in 2014 and Santa Clara in 2016) showed an increased electricity demand in the hours preceding the game, while all three host regions showed a general decrease in electricity demand during the game.

While these data are not complete or detailed enough to make definitive conclusions (in addition to the lack of more years of historical data, the issue of controlling for the weather is difficult to do since some of the wider regions will have more varied temperatures throughout the region and make it more difficult to ensure the weather is not causing electricity fluctuations as a whole), they do generally follow the results of U.S.-wide studies. A study by Outlier found, through working with utilities during Super Bowl 46, the following:

More specifically, versus a typical Sunday afternoon/evening in the winter, home power usage was 5 percent lower during the Super Bowl, with big consequences for overall energy use:

Source

Going further, ISO New England’s minute-by-minute graphical analysis during Super Bowls 49 and 50 show the types of effects the big moments like the start, halftime, and end of the game have on the total demand load (and also serve to solidify that the effects are more pronounced when a region’s local team is in the game!)

Source

 

Explanation of the trends

The conclusion of less electricity usage over the course of the Super Bowl may sound surprising at first, given that it’s an event centered around an electronic device in the TV, but when you break it down it really makes sense. While it’s true that Americans gather around the television, they are often doing so collectively– going to parties or bars. So while the Super Bowl is often uncontested as the most watched television program of the year, that does not necessarily lead to an increase in the number of television sets being powered as people congregate around TVs together. These effects are going to be even more drastic if a local team is in the game (drawing in the more casual viewer) or if the game is being played locally (meaning more people will be in or near the stadium to enjoy the festivities).

Further, just because people are turning on their TVs does not indicate that household energy use is going up. That is because TVs require less than 400 Watts (W), and sometimes as few as 20 W, compared with most energy-sucking appliances like the vacuum (650 W), washing machine (2,500 W), or water heater (4,000 W). During the Super Bowl when the TVs are on, households are significantly less likely to be using these more electricity-consumptive appliances (not to mention many households would regularly have their TVs on during these hours anyway) and thus overall electricity demand noticeably drops.

That combination of people gathering together as opposed to being in separate households and using TVs instead of other appliances satisfyingly explains the drop in power use during the game. We could also conjecture that power use goes up before the game as people are getting the energy intensive chores (washing clothes, vacuuming, washing dishes, etc.) done earlier in the day before heading out to their Super Bowl gathering. They might also be preparing food to enjoy during the big game using their ovens/microwaves/stove tops in these early afternoon hours when they would not normally be in the kitchen.

Exceptions to the trends

Though the previously discussed trends were found in a majority of the cases analyzed in this article, there were a couple that bucked the trend. Specifically, analyzing the electricity use on Super Bowl Sunday compared with a comparable Sunday found that:

  • In 2017, both New England and Atlanta, as well as host city Houston, had lower than normal electricity demand in the hours before the game;
  • In 2016, the Carolina region saw large peak in electricity use compared with normal in the afternoon leading up to the game; and
  • In 2015, New England had increased electricity demand the morning of the Super Bowl as well as during the game.

There are a number of potential reasons that these specific instances did not meet the trends found in other places. The main one could be that while the average temperature used to find a comparable Sunday was close to the temperature on Super Bowl Sunday, there could have been wildly varying temperatures in different parts of the region or in different times of the day that prompted heating or cooling systems to be ramped up. Without the availability hourly temperature data and/or the analysis of temperature data of many cities within a region, it is impossible to know for sure. Further, grid operators also monitor aspects of weather like dew point, precipitation, cloud cover, and wind to predict electricity demand– which would be significantly more difficult for me to control for here. So for aberrations outside of the expected trends, these type of weather effects are the most likely culprit.

Another interesting explanation to look for is how captivating a particular game might have been. In its analysis of Super Bowl energy numbers, MISO notes that the more captivated and the more glued to their seats watchers are during the game, the more the demand will remain steady and low. As soon as people start to get up and do other things in the house (either because its halftime or a game is uninteresting), they notice a real uptick in electricity demand. This effect could perhaps explain why electricity use started to go closer to normal levels in New England in 2017 when the Patriots were building a seemingly insurmountable deficit, and it could also explain why electricity demand started to increase compared with normal in Carolina in 2016 about midway through the game (while never down by more than 10 until the closing minutes, more casual Panthers fans might have been frustrated with their team’s lackluster offense and inability to score more than 7 points through the third quarter and tuned out to partake in more energy-intensive activities).

Methodology

Availability of data

The availability of a region’s electricity demand depends on the entities who deliver energy and how far back in time you are looking. At the suggestion of the Federal Energy Regulatory Commission (FERC), a number of regional transmission organizations (RTOs) and independent system operators (ISOs) have been established in the United States to coordinate, control, and monitor complex and sometimes multi-state grid systems. One of the results of the use of these systems is they often make hourly electricity demand data publicly available going back a number of years, which allows for us to look back on some of the regions of the participants/hosts of the Super Bowl. The cities/years where those data are available are shown in the table below.

For regions that are not a part of RTOs or ISOs, unfortunately the electric companies rarely make public the same type of data. However a proxy we can utilize the Energy Information Administration’s (EIA) Electric System Operating Data tool. While it only goes back to the summer of 2015, it does provide the same type of hourly electricity demand data for regions and utilities outside of RTOs/ISOs. So where needed, this data is used as well as indicated in the below table.

When going back to Super Bowl 49 and earlier, some data become unavailable and those cities are not included in the analysis, shown below as ‘not available.’

 

For links to each of the electricity data sources listed in the above table, go to the ‘Sources and additional reading‘ section.

Finding a reasonable day for comparison

To determine the changes in electricity demand that are attributed to each region for Super Bowl analyzed, a reasonable day for comparison was found in each region using the following criteria:

  • As pointed out in the previous post analyzing electricity usage during a federal government shutdown, nothing will affect a region’s power demand more than the weather. If all buildings and homes are turning up either the air conditioning or the heat, that will have a greater effect on electricity usage than anything else– even an event as large as the Super Bowl. With the goal of comparing electricity demand on Super Bowl Sunday with other days and controlling for other factors, the methodology used was to assure that the comparison day chosen had an average temperature as close as possible to the average temperature on the day of the Super Bowl in that region. As a rough proxy, the average temperature on the day of the Super Bowl in the major city associated with each team/region was found on Weather Underground, and the goal was to find a comparison day with an average temperature within a few degrees Fahrenheit;
  • There are also distinct patterns to electricity demand depending on the day of the week, so the comparable day chosen was always made to be a Sunday; and
  •  Lastly, the comparable day chosen was kept to be within one to three weeks of the Super Bowl (either before or after), while avoiding any Sunday that had a playoff football game for the region’s home team, to assure any other externalities are kept as constant as possible.

With that criteria in mind, the following were the days used for comparison to Super Bowl Sunday in each region:

Click to enlarge

Graphical comparisons

Once the hourly data for each Super Bowl Sunday and chosen comparable dates were pulled, the hour-by-hour comparison is calculated using a simple percentage change from the regular non-Super Sunday. These percentages are what are ultimately graphed on an hourly basis, with the up to three regions (depending on how many available) on the same graph to see if there are any trends based on the cities. Similar comparison was not included for overall U.S. electricity trends because the large and varied geography of the United States makes controlling for the effects of weather on electricity demand much more complicated and difficult (however, as noted earlier, a study that looked at thousands of households during the 2012 Super Bowl found that an on overall basis, electricity demand increases on Super Bowl Sunday in the hours before the game and decreases once the game begins).

Sources and additional reading

5 Facts About Energy During the Big Game: MISO

Baltimore Gas & Electric: PJM RTO

California ISO: Pacific Gas & Electric electricity demand

Carolinas region electricity demand (EIA)

Energy Reliability Council of Texas (RTO) Coastal Region Electricity Data

How a Patriots Super Bowl affects the region’s power grid: ISO Newswire

How the Super Bowl saves energy: ABB

New England ISO Electricity Data

Northwestern region electricity demand (EIA)

Public Service Company of Colorado (EIA)

Public Service Electric & Gas Company: PJM RTO

Regional Transmission Organizations (RTO)/Independent System Operators (ISO): FERC

Southeastern region electricity demand (EIA)

Why people use less energy on Super Bowl Sunday: Washington Post

 

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Federal Government Shutdown: Analyzing Electricity Demand When Government Workers Get Furloughed in Washington DC

In a dance that’s become a bit too commonplace in the federal government, threats of a government shutdown over political differences and budget issues are looming once again. After multiple continuing resolutions agreed to between Democrats and Republicans, the latest deadline for appropriation bills to fund the government is fast approaching. While a potential government shutdown would put my 9-5 job on hold until a resolution was reached, a frustrating prospect for all families who rely upon paychecks from their government jobs, there’s not much to do for those of us outside of the White House and Congress. What I can do with that nervousness, though, is ask energy-related questions!

The fact that energy and electricity use changes at regular intervals throughout the day and week is well established, and these trends are reliably correlated with the day of the week, time of the day, and weather. Knowing this led me to the question of how a government shutdown would effect the electricity demand in the Washington DC area, where over 14% of the workforce is made up of federal employees. Would a government shutdown lead to an electricity demand closer to a typical weekend day than a weekday because of the large amount of people who would no longer be reporting for work? Would the overall electricity demand go up or down? Is any of this even noticeable, given that about 86% of the workforce would be going to work as normal? We are only four years removed from the last federal government shutdown, so looking at the electricity demand surrounding the 2013 shutdown can provide some insight as to what might happen if there is a shutdown this time around.



Background

The 2013 federal government shutdown lasted from October 1 through October 16, with President Obama signing a bill to reopen the government shortly after midnight on October 17. The political football at stake in 2013 was the Affordable Care Act, as Republicans in Congress sought to defund the program while the Democrats refused to pass funding bills that would do so. As a result, nearly 800,000 non-essential federal employees across the country were out of work without pay, while about 1.3 million essential employees reported to work as normal (though they saw their paychecks delayed). At the heart of the potential 2018 shutdown is the political debate surrounding immigration policy, though the effects on government workers would likely be largely the same as in 2013.

Source

While these numbers account for the vast amount of federal employees furloughed outside of Washington DC (such as employees in National Parks across the country), they still included a large number of DC residents. Further, employees of government contractors were reportedly sent home and furloughed without pay as well, though the data surrounding exactly how many government contracts were affected is unclear. So while there are other metropolitan areas that have a larger percentage of their workforce employed by the federal government, the prominence of federal contractor workers in DC still makes it an obvious choice for examining how the electricity demand changed in the wake of the 2013 federal government shutdown. More importantly, though, this analysis will focus on Washington DC because the data from the power companies is available in a sufficiently granular way for the region. The Potomac Electric Power Company, or PEPCO, is the electric power company that serves the entire city of Washington DC, as well as the surrounding communities in Maryland, so looking at PEPCO’s data over the shutdown dates will enable insights into the effect of the shutdown. Federal workers in other regions are typically served by much larger power companies (such as Dominion Energy in Virginia serving many of the Northern Virginia communities of federal workers in addition to the rest of Virginia and parts of North Carolina), making the potential effect on the power delivery data from the shutdown less significant on a relative scale.

Data and graphics

PJM, the regional transmission organization that coordinates the movement of wholesale electricity in 13 states and DC, makes available PEPCO’s metered electricity load data on an hourly basis. This type of data is available for most U.S. power companies, which is fun to play with to get an idea of how Americans behave during certain events like holidays, the Super Bowl, or any other large-scale event. In order to get a baseline of what the weekly electricity distributed by PEPCO, we can first look at the two weeks leading up to the government shutdown of 2013:


A couple trends become clear looking at these two seemingly normal weeks. First, the weekends (with Saturday and Sunday graphed using a dashed line instead of the solid line for weekdays) appear to have less electricity demand compared with weekdays. This trend is noted everywhere, not just DC, as weekends are when typical commerce activity drops. Additionally, there are clearly patterns of high and low electricity use by time of day, regardless of weekend or weekday. Demand appears to be at the lowest late at night and early in the morning when most people are sleeping, ramp up in the morning as people wake up to begin their day, and peaks around 5 PM when people are coming back home, making dinner, turning on the TV, putting laundry in the washing machine, etc. But did any of these trends change during the 2013 federal government shutdown? Here is the same data for the three calendar weeks during which the government was shut down:


When comparing these graphs with the two weeks prior, there does seem to be some noticeable differences– though the differences vary between the three weeks the shutdown was effective:

First Week

  • To start, the peak and cumulative power use appears to have increased a significant amount during the first week of the shutdown– though that could always be caused by the weather and a need to increase air conditioning or heating in a home. Indeed, looking at the temperature (discussed more later), the average temperature during the week climbed from about 66 degrees Fahrenheit the week before to about 73 degrees Fahrenheit. A possible explanation is the higher power use coming from people turning on their AC for the first time in a while due to unseasonably warm temperatures.
  • The overall ‘shape’ of the curves remain constant, so the furloughed employees and contractors did not appear to change their daily patterns enough to shift the timing of peak and minimum electricity loads.
  • Also interesting to note is that the Sunday before the shutdown (Sep. 29) stays lower than the weekdays, as was noted to be typical of weekend days, but the Saturday following the shutdown (Oct 5) then shifts to be among the days with the greatest electricity demand. I wasn’t expecting the furloughing of employees to have much of an effect on the weekend electricity demand, as most of the furloughed federal employees presumably did not typically work on weekends, but the answer can likely be attributed to weather as the weekend of Oct 5-6 had the warmest temperatures (79 and 80 degrees Fahrenheit, respectively) of the whole analysis period.

Second Week

  • The second week is the most anomalous of the three, with Sunday and Monday having the shape of the curve significantly affected and also having much higher peaks than the rest of the week (whereas the first week increased the peaks more comparably among the days of the week). In terms of why Sunday might have shifted so significantly, a search of what might have happened in Washington DC to cause this change on October 6, 2013 turned up an article about an explosion accident on the Metro. Perhaps the emergency response to this incident caused significant effects to the electricity demand?
  • Outside of Sunday and Monday, the peaks and shapes of the demand curves were back to being comparable to pre-shutdown levels. As will be shown shortly, though, this trend looks to be attributable to the returning of temperatures to an average of 65 degrees Fahrenheit.

Third Week

  • By the time of the third and final week of the shutdown, the electricity demand curve looks to be mostly back to normal. The last Sunday of the shutdown and the first Saturday after the shutdown look like normal weekend days, while the weekday curves look normal all week, even though the furloughed government employees and contractors did not head back to work until Thursday.

Just to be complete and ensure the trends we saw before and during the 2013 federal government shutdown were not just random week-to-week variations, below are the same graphs for the two weeks following the shutdown:

These two weeks show somewhat the same general trends we saw prior to the shutdown, with the main changes being that the peak demand for each day appears to be shifted to first thing in the morning when people are waking up and the morning of Saturday Oct 26 showing a higher peak than is typically expected of a weekend day. The peak electricity demand shifting to the morning likely comes from the weather getting colder (down to average temperatures of 53 and 59 degrees Fahrenheit, respectively), while the early peak electricity demand on Saturday Oct 26 might have been caused by a rally protesting mass surveillance that attracted thousands of people to Washington DC (though it too is likely in part due to the fact that it was the first day of the season where the average daily temperature dipped to 46 degrees Fahrenheit and people cranked the heat up when they woke up shivering that Saturday morning).

In addition to the demand curves, it’s important to look at the total daily electricity consumed by day over these previously discussed weeks, while also comparing these totals to the average daily temperatures in DC as I’ve done through the previous analysis:

As these two graphics demonstrate, the total electricity demand mostly moves step-in-step with the daily weather regardless of whether or not the federal government is open. If it gets too warm or too cold, that is when you see the spikes in electricity demand– and that will always be the most significant factor.

Conclusions

In the end, there does not appear to be a significant effect on Washington DC’s electricity demand during a federal government shutdown. While having thousands of employees and contractors stay at home is certainly not trivial, there are still even more government employees who would be deemed ‘essential’ and would be in the federal buildings (who would still be operating their heating/cooling systems). Beyond that, a vast majority of PEPCO customers are not in the federal workforce, so the change in daily habits of the unfortunately furloughed employees does not move the needle in a noticeable manner in terms of electricity demand. What’s more important to consider is the weather, and perhaps any daily events such as the Metro accident or the anti-surveillance rally. So while no one, especially in DC, is rooting for a federal government shutdown this week (the 2013 shutdown cost the country $24 billion and disrupted Veterans Affairs benefits from being sent out), we can take incredibly small solace that it won’t disrupt the expected electricity demand. Despite liquor sales increasing during the 2013 shutdown, the thousands of workers who would find themselves temporarily out of work would not have their change in daily routine threatening the electrical grid’s behavior.

If this type of data is of interest to you, by the way, the Energy Information Administration has an amazing tool that allows you to track electrical demand across the country in real-time. Are there any other events you think would be interesting to investigate for their effect on electricity demand? Let me know in the comments!

Sources and additional reading

Absolutely everything you need to know about how the government shutdown will work: Washington Post

Customer Base Line: When do you use the most electricity? Search for Energy

Demand for electricity changes through the day: Energy Information Administration

Democrats face make-or-break moment on shutdown, Dreamers: Politico

Electricity demand patterns matter for valuing electricity supply resources: Energy Information Administration

Electricity supply and demand for beginners

Everything You Need to Know About the Government-Shutdown Fight: New York Magazine

Here’s What Happened the Last Time the Government Shut Down: ABC News

How Many Federal Government Employees Are in Alexandria? Patch

Metered Load Data: PJM

U.S. Government Shutdown Looms Amid Immigration Battle: Reuters

Which Metro Area Has the Highest Share of Federal Employees? Hint: Not Washington: Government Executive

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

How Much Power Is Really Generated by a Power Play?

As a huge sports fan who works in and writes about the energy industry, stumbling across this article that compared the kinetic energy produced by the high velocity projectiles in different sports got my creative juices flowing. By the estimates in that article, shooting a hockey puck produces the highest kinetic energy in all of sports.

Not only does it appear that hockey can take the ‘energy crown’ in sports, but a common occurrence during a hockey game is a ‘power play.’ A power play occurs when the referee determines that a player has committed a foul and that player is sent to spend a set number of minutes in the penalty box. During that time in the penalty box, the opposing team has the advantage of one additional player and are said to be on a power play– and if they score during that time then it is called a power play goal. While this power play has absolutely nothing to do with power plants or power generation, the idea that hockey pucks have the most kinetic energy in sports got me to wondering about what sort of power generation could be harnessed by power play goals in the National Hockey League (NHL).



If we wanted to harness the power of power plays (why would we want do do that? Maybe it’s the part of a plot by a wacky cartoon villain!), how much would that be? Why don’t we sit down and do the math!

Energy from a hockey puck

To start, we need to determine what the energy of a single hockey shot should be assumed to be (as the previously mentioned article does not include all of the necessary assumptions for academic rigor). High school physics class taught us that the kinetic energy is determined by taking one half times the mass of the object times the square of the speed of that object.

Source

Official ice hockey pucks weigh 170 grams, so we just need to figure out what to assume as the speed of the puck. Obviously every shot of the puck comes at a different speed depending on who is shooting, what type of shot is used (e.g., slap shot vs. wrist shot), how fatigued the player is, the condition of the ice, and many other factors. But for the sake of this back-of-the-envelope calculation, we can look at a couple of data points for reference:

  • The official NHL record for shot speed is 108.8 miles per hour (MPH) by Zdeno Chara in the 2012 All-Star Skills Competition;
  • Guinness World Records recognizes the hardest recorded ice hockey shot in any competition as 110.3 MPH by Denis Kulyash in the 2011 Continental Hockey League’s All-Star Skills Competition;
  • When discussing the benchmark of a particularly strong slapshot, 100 MPH is often used as the benchmark of a player getting everything behind a shot;
  • Finding benchmarks for the wrist shot is not as prevalent (people like to discuss the hardest shots possible, hence data on slap shots and not wrist shots), but some estimates show that wrist shots can reach speeds of 80 to 90 MPH; and
  • Estimates put wrist shots as accounting for 23 to 37 percent of all shots taken in professional hockey.

Given those figures, a rough estimate of average NHL shot speed can be determined by assuming slap shots are about 100 MPH and account for 70 percent of shots, while wrist shots are about 85 MPH and account for 30 percent of shots:

For the sake of this exercise, we’ll call the speed of a NHL shot 95.5 MPH, which equals about 42.7 meters per second (m/s). Plugging that speed and the 170 gram weight of the puck into our kinetic energy equation leaves us with an assumed ‘Power Play Power’ of an NHL power play goal of 154.9 Joules (J)– just over 0.04 kilowatt-hours (kWh).

For the rest of this article, we’ll refer to the energy gathered from power play goals, 154.9 J at a time, as ‘Power Play Power’– though please keep in mind the cardinal rule that power is the rate of energy over time, while the Joules and kilowatt-hours we’re talking about is total energy

Source

How much power can be harnessed from power plays?

The next step in reality would be to figure out how exactly you intend to extract ‘Power Play Power’ into actually generated energy, though that can be left up to the hypothetical cartoon villain who would be using such odd methods to create energy for his evil plots, as he did with the champagne bottles on New Year’s Eve (Side note, if I continue to write articles about the bizarre energy sources only thought up by a misguided cartoon villain, he needs a name– so in the spirit of villains like Megatron, Megamind, and Mega Shark, the energy-obsessed villain will be named Megawatt!)

But ignoring the question of how or why we would be extracting energy from ‘Power Play Power,’ let’s just look at what type of power will be generated based on 154.9 J per power play goal. Also note that there’s nothing special about the energy generated by a power play goal compared with a regular goal or even a shot that misses the goal– but where would the fun be without wordplay? POWER play goals only!

Most individual power play goals in a season

Note that all of the statistics pulled for this analysis are current as of January 1, 2018. Any power play goals scored after that date will not be accounted for in these statistics and calculations.

Pulling the top 10 individual player seasons with the most power play goals in NHL history, and assuming each of those power play goals account for 154.9 J, gives the following results:
Despite an impressive 34 power play goals in the 1985-86 season, Tim Kerr’s NHL record season would only generate enough ‘Power Play Power’ to run a large window-unit air conditioner for one hour at almost 1.5 kWh.

What about considering single players over their entire career?

Most individual power play goals over a career

As of January 1, 2018, the top 10 power play goal scorers for an entire career are as follows (note that as of writing, Alex Ovechkin is still active, as is Jaromir Jagr who is only two power play goals behind him in 11th place):
Looking at Dave Andreychuk, the individual with the most career power play goals in NHL history, his career ‘Power Play Power’ accounts for almost 11.8 kWh. Despite being an incredibly impressive number of power play goals, it’s only enough to power an energy-efficient refrigerator for about a week and a half. That’s a useful amount of energy to use in your home, but when it takes 274 career power play goals that that might be more work than it’s worth…

However looking at these first two charts, one aspect really jumps out– players who come from Canada appear to dominate ‘Power Play Power’ generation! Let’s dig into that a bit more.

Most power play goals by country of origin in the NHL

To start, Quant Hockey’s data shows that there are only 25 different home countries across all the players who have ever scored a power play goal in NHL history. Those 25 countries are listed in the below chart with their respective ‘Power Play Power’ totals generated:

Now we’re talking about some real energy. Canada, as predicted, dominates with almost 2,250 kWh of ‘Power Play Power’ since the beginning of the NHL. This amount of energy equates to about 20% of the average annual electricity used by an American household in 2016.

So that’s a pretty significant amount of energy on a micro-scale, but because we’re talking about the total ‘Power Play Power’ generated by all Canadian NHL players over nearly a century of play it is still not terribly impressive. For reference, the smallest nuclear power plant in the United States has a generation capacity of 582 Megawatts, meaning the 2,250 kWh of ‘Power Play Power’ of Canadian NHL players would be generated in under 14 seconds by the smallest U.S. nuclear plant operating at full capacity. Even if we included all power play goals scored by players of any nationality, the total ‘Power Play Power’ would only reach 3,339 kWh– or almost 21 seconds from the smallest U.S. nuclear plant.

Source 1, Source 2

Obviously the actual energy generation of each of these 25 nations will be much greater than the ‘Power Play Power’ generated by their respective NHL players– but is there some sort of correlation between ‘Power Play Power’ and actual energy production of the nations? Using the silly initial premise of this article as an example of the type of information available from the Energy Information Administration (EIA), a part of the U.S. Department of Energy, and how to find that data, we can pull the total primary energy production for these 25 countries and get a rough idea! While the NHL started recording power play goals in the 1933-34 season, EIA’s country-by-country energy production data dates back to 1980 (measured using quadrillion British thermal units, or quads), but we’ll still use these two complete time frames for the comparison’s sake. Putting the two energy figures on one graph for a relative comparison provides the following:
This graph presents a couple of interesting points:

  • Among the 25 eligible nations included in the survey, Canada, the United States, and Russia all find themselves in the top 4 countries in terms of both ‘Power Play Power’ and Total Primary Energy Produced by the nation;
  • In an interesting coincidence, when the two types of energy being measured here are put on comparative scales, Canada and the United States appear to be almost mirror images of each other, swapping relative strength in ‘Power Play Power’ and Total Primary Energy Production;
  • In another similarity between the two measures of energy, the totality is dominated by the top three nations, and the relative scale of any nation after about the halfway point shows up as barely even a blip on this graph.

But other than that, it can be considered fairly unsurprising that NHL power play success doesn’t directly translate to Total Primary Energy Produced by nation. And even if Canada saw their NHL power play prowess as their opportunity to increase energy exports (which would only serve to increase the fact that Canada is the largest energy trading partner of the United States), translating ‘Power Play Power’ into real energy, their 2,250 kWh over NHL history would only translate to 0.00000004% of Canada’s primary  energy produced in 2015 alone. Unfortunately, I do not think I’ve discovered a viable energy to be harnessed by the villainous Megawatt.

Source

More benevolently, it would also appear that ‘Power Play Power’ will not serve as a reliable new renewable energy source for hockey-crazed areas (in this scenario, are we to consider penalty minutes a source of renewable energy?? If so, Tiger Williams might be the most environmentally friendly player in major sports history). However, at 419 billion kWh of renewable generation in 2015, Canada is the fourth largest renewable energy producer worldwide (with the United States and Canada being the only nations this time to finds themselves in the top four of of renewable energy and ‘Power Play Power,’ as North America accounts for majority of NHL players and has collectively agreed to generate 50% of electricity from clean sources by 2025). Following the link for EIA international renewable energy data to bring this back to educational purposes, you’ll find other top-15 ‘Power Play Power’ nations that also account for the top-15 in global renewable energy production, including the United States, Germany, Russia, Sweden, and the United Kingdom.

Coincidence? Probably.

Interesting and informative, nonetheless? Definitely!



Sources and additional reading

Appliance Energy Use Chart: Silicon Valley Power

Comparing Sports Kinetic Energy: We are Fanatics

How much electricity does a nuclear power plant generate? Energy Information Administration

How much electricity does an American home use? Energy Information Administration

Iafrate breaks 100 mph barrier: UPI

International Energy Statistics: Energy Information Administration

Most Power-Play Goals in One Season by NHL Players: Quant Hockey

NHL & WHA Career Leaders and Records for Power Play Goals: Hockey Reference

NHL Totals by Nationality – Career Stats: Quant Hockey

Now You Know Big Book of Sports

Ranking the 10 Hardest Slap Shots in NHL History: Bleacher Report

Saving Electricity: Michael Bluejay

Scientists Reveal the Secret to Hockey’s Wrist Shot: Live Science

Score!: The Action and Artistry of Hockey’s Magnificent Moment

Sherwood Official Ice Hockey Puck: Ice Warehouse

Slap Shot Science: A Curious Fan’s Guide to Hockey

Total Renewable Electricity Net Generation 2015: Energy Information Administration

Wrist Shots: Exploratorium

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

The Hidden Energy of New Year’s Eve Celebrations, Measured in Joules

As a final post for the year, I thought I would channel some of my earlier holiday/energy crossovers (Halloween, Thanksgiving, and Christmas/Hanukkah/Kwanzaa all got energy-related analyses this year!) and have a fun and quick look at some energy figures associated with celebrating New Year’s Eve. Whether you head out to a wild and exclusive party, stay in and toast a quiet New Year with your family, or fall somewhere in between, you’re sure to stumble across one of the users of energy described here. So toast to a good 2017, and even better 2018, and learning more mostly-pointless but still-fun energy trivia!



Popping champagne and the Times Square Ball

A surprising amount of scientific research has been done on the science of champagne bottles– filling them, storing them, and opening them. Fortunately for the purposes of this article, there was even a fairly extensive research paper conducted on the physics of popping the cork of the champagne bottle.
According to the study published in the Journal of Food Engineering, the velocity that a champagne cork shoots out of a bottle of champagne varies based on the temperature of the champagne. Consistent with the idea that increased temperatures correlate with increased pressures, the study found that at 4 degrees Celsius the cork shot out at about 38 kilometers per hour (km/h), but that speed increased to about 48 km/h at 12 degrees Celsius and about 54 km/h at 18 degrees Celsius.

Source

By consulting Wine Spectator, it appears the optimal temperature at which to serve champagne is 55 degrees Fahrenheit, or about 12.8 degrees Celsius. If we assume a roughly linear relationship between temperature and cork speed (as shown in the graph below), that would mean the ideal champagne bottle’s cork would pop at about 47.6 km/h.

The basic formula to calculate the kinetic energy of a moving object is 1/2 times mass times velocity squared. Plugging in the mass of the cork (which the study gave at about 10 grams) and the velocity (47.6 km/h or 13.2 meters per second), the cork has a kinetic energy of about 0.9 Joules (J).

While 0.9 J does not sound like that much (as discussed in the post about energy units, a single Joule is the energy required to lift an apple 1 meter off the ground), keep in mind that flying corks can still be dangerous, and if one hits you in the eye it can ‘cause a shockwave that can lead to hemorrhage, disruption of tissues, a cataract, even retinal damage.’

Also worth noting is that the flight of the champagne cork is only a small part of the energy in opening a champagne bottle. The same study that looked at the speed of the cork also found that only about 5% of the energy released when a champagne bottle is opened gets transferred to the kinetic energy of the cork, with the rest being converted to the ‘pop’ sound, a small amount of generated heat, and a cloud of gaseous carbon dioxide (CO2) gushing out of the bottle. If the 0.9 J behind the cork is only 5% of the total champagne opening energy, that would mean the total energy associated with the opening of a champagne bottle is about 17.5 J.

Given this knowledge, what if we wanted to calculate something ridiculous– like how many champagne corks popping it would take to power the Times Square Ball that’s dropped on New Year’s Eve (seems like this could loosely be the plot to an odd children’s book, or the first part of a plan hatched by a cartoon villain)? For the 100th anniversary of the Times Square Ball drop, the ball was updated with over 32,000 state-of-the-art LEDs, which made the lit up ball 80% more efficient than it previously had been with halogen bulbs. The end results is that the lit ball now only requires 50 kilowatt-hours (kWh) of energy for the New Year’s Even celebration. Converting that figure to Joules gives a total energy use of 180,000,000 J.

Source

So what does that mean for our ‘power the Times Square Ball by opening champagne bottles’ scheme? If we’re harnessing the energy of just the corks flying out of the bottles (at 0.9 J per cork), then 205,687,545 bottles of champagne will need to be uncorked. Given that 2 million people attended the Times Square New Year’s Eve celebration to ring in 2017, that would mean every person in attendance would need to uncork just under 103 bottles of champagne each. BUT– if we instead are able to harness the entire energy from the champagne uncorking (which brings the total energy per bottle to 17.5 J), then only 10,284377 bottles of champagne are required, or just over 5 bottles per attendee of the Times Square celebration. That’s much more doable! In fact, the Guinness World Record for champagne bottles opened in one minute is 10, so all that’s left is for these misguided champagne powered villains to figure out is how to harness all that energy.

Party poppers and fireworks in Sydney

Another common feature to midnight celebrations are party poppers– those mini explosive doodads that explode with a loud bang and a pop of confetti and/or streamers when you pull on the string. Many people don’t realize that these party poppers actually contain explosive powder, though in small enough quantities that they are not legally considered fireworks and can thus be old in any grocery or party store. But given the limited firepower allowed, exactly how much energy is contained in these almost-fireworks that we give to children and drunken party-goers alike?

Source 1 Source 2

While most real firecrackers are limited by law to 50 milligrams (mg) of gunpowder, the party poppers that are sold in stores are capped out at 16 mg of gunpowder each. Given that gunpowder has a specific energy of 3.0 Megajoules per kilogram, we can calculate that each party popper contains 48 J of explosive energy.

Now what if we considered the firepower of these party poppers in the context of another explosive New Year’s Eve tradition– fireworks! Among the largest and most famous New Year’s Eve fireworks displays (also famous due it taking place in one of the earliest time zones to celebrate the New Year) is the annual Midnight Fireworks in Sydney, Australia. How many of the dinky party poppers would it take to equal the firepower in this massive fireworks display? This calculation is the most ‘back-of-the-envelope’ type one here, but some reasonable estimates can be made.

Source

First, start with the knowledge that the Midnight Fireworks to celebrate 2017 in Sydney featured 8 metric tons of fireworks. Then take the rule of thumb that the explosive flash powder of fireworks makes up about 25% of the weight of the overall weight of the fireworks, leading to an estimate that the Sydney fireworks required 2 metric tons (or 2 million grams) of explosive flash powder. Combine that with with energy density of flash powder of 9,196 Joules/gram to arrive at an estimated energy content of the Sydney Midnight Fireworks of 18.292 Gigajoules, or 18.392 billion J.

Over 18 Gigajoules is a massive amount of explosive energy, an an equally impressive number of party poppers. Given each party popper supplies 48 J of energy, you’re looking at 383,166,667 total party poppers. What would be required for those in attendance at the Sydney fireworks display to match the firepower of the fireworks with party poppers (yes, our cartoon villain with poorly designed schemes has come back and is trying to take over the world with party poppers!)? Since the 2017 fireworks display in Sydney clocked in at 12 minutes long, that means the crowd of people popping party poppers would need to average 31,930,556 party poppers per minute. Combine that figure with the attendance of the Sydney Midnight Fireworks (which was about 1.5 million) to find that, in order for the crowd in attendance to equal the firepower of the actual fireworks, each person would need to pop just over 21 party poppers per minute. While a party popper every 2.82 seconds for 12 minutes by 1.5 million different people seems like a crazy high number, the Guinness World Record for party poppers popped in a minute (because of course that’s a record) is 78 in one minute. As such, the 1.5 million in attendance would only need to go at 27% of the world record pace– once again, totally doable. Though be careful, because the party poppers are also known to cause ocular injury— especially when a million and a half people are each firing off over 250 poppers each in such close proximity.

Sources and additional reading

Are Fireworks Legal in Your State? Laws and Regulations: Something About Orange

Ask Dr. Vinny: Wine Spectator

Champagne cork popping revisited through high-speed infrared imaging: Journal of Food Engineering

Chemical Potential Energy: The Physics Hypertextbook

How Dangerous Are Champagne Corks, Really? Motherboard

How do Party Poppers Work? eHow

How Much Energy Do Fireworks Generate on July 4th? Ecovent

Incredible rainbow waterfall from the Harbour Bridge using eight tonnes of fireworks: Sydney’s New Year’s Eve 2017 set to be the biggest ever: DailyMail

LEDs Light up New Years Eve 2010 in Times Square NYC! inhabitant

NYE History & Times Square Ball: Times Square Official Website

Party popper: Wikipedia

Pressure Systems Stored-Energy Threshold Risk Analysis: Pacific Northwest national Laboratory

Renewable ‘pedal power’ to light Times Square ball tonight: VentureBeat

Sydney’s New Year’s Eve Fireworks Pay Tribute to Prince, David Bowie and Gene Wilder: Time

‘The energy here is like out of conrol’: Times Square kicks off American New Year celebrations: CBS News

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Powering the Holiday Symbols: Energy and Emissions of Christmas Trees, Hanukkah Menorahs, and Kwanzaa Kinaras

The holiday season has a handful of hallmark indicators that announce its arrival– the immediate overtaking of popular radio, jack frost forcing you to bust the heavy jackets out from the back of the closet, and the increased crowds at malls everywhere. But if those harbingers of the upcoming festivities elude you, the season has one surefire signal that pops up everywhere to grab your attention– the decorations!

Specifically, as soon as Thanksgiving is over, youwould have to live under a rock not to notice the twinkling lights adorning storefronts, lamp posts, and porches across the country. Whether they’re for Christmas, Hanukkah, or Kwanzaa, lighting is an important part of the holiday season. That got me to pondering, naturally, about the relative energy use of lights and candles for each of these three holidays and their signature decorative centerpieces– the Christmas tree, the Hanukkah Menorah, and the Kwanzaa Kinara. I was interested not only in the question of how the energy use required by these three decorations compare with each other, but also what is the most efficient way to light each of them for the energy-conscious celebrator? Also, how do these three symbols of their respective holidays stack up in terms of carbon dioxide (CO2) emissions?

If these questions have been nagging you since you first spotted Christmas decorations for sale at Target in October (and I know they have), then you’re in luck. Keep reading for some estimates, assumptions, back-of-the-envelope math, and analysis and conclusions!

Preemptive notes

  • As had to be recognized in the other holiday posts (Most Climate Friendly Way to Light Your Jack-O’-Lantern and Talking Turkey: Thanksgiving Dinner Energy Use and Carbon Dioxide Emissions), these calculations are based on some liberal assumptions and over generalizations that are traced to readily available information. There will obviously be differences in the final calculations depending on a variety of factors– number of lights, how long the lights and candles are left on and lit, and numerous other variables that differ from household to household. While each assumption will have a citation to where it originated, rest assured that the final answers will still only be general back-of-the-envelope estimates. If one of the numbers or assumptions looks off, please comment below and discuss! Otherwise, just recognize that the goal is to find these rough estimates based on available information and general conclusions that are in the right order of magnitude for the sake of comparison, discussion, and general insight.
  • Also, it goes without saying that there are many more uses of energy associated with the holidays that are not being accounted for here– especially if you factor in outdoor Christmas lighting (e.g., were you to go as crazy with the outdoor illumination as Clark Griswold, you would be staring at an additional 27.7 kilowatts of additional power usage). This article is ignoring those other uses and is just interested in answering to the average energy use of Christmas trees, Menorahs, and Kinaras, including the range for both the less-efficient and more-efficient options among those three.

Christmas tree and lights

Basic assumptions

To break down the energy and carbon costs of lighting your Christmas tree, a number of very simplified assumptions need to be made about the average Christmas tree and its use. Again, keep in mind that these figures can vary greatly depending on the choices made by the individual household, but we’ll use the following assumptions:

  • There is no standard number here, but for the sake of calculation we will assume that the Christmas tree lights are on for 5 hours every night, as estimated by Christmas Lights Etc.; and
  • Much discussion exists out there for how many days a Christmas tree should be up in a house, with some sources estimating the average tree gets put up the first week in December and taken down sometime between Christmas and the New Year. Another traditional time to put up your tree is the first day of Advent, which this year falls on December 3 (coinciding with the first weekend of December). For 2017, we’ll assume families put up their tree on Sunday December 3 (first weekend of December, first day of Advent) and take them down the first weekend after Christmas– Saturday December 30– for a total of 27 nights the tree will be decorated (obviously this is a key variable that can change based on household habits).

Energy use of Christmas lights

For the Christmas lights used, let’s examine two options using traditional incandescent lights and one using more efficient LEDs. The actual wattage of these options will also vary depending on the specific light chosen, but for the sake of calculation we’ll use the following:

  • As our starting point, we’ll use the top hit on Amazon.com for incandescent Christmas lights. This package comes with 25 bulbs at a power of 7 Watts (W), meaning these lights use 0.280 W/bulb;
  • We’ll also look at the mini incandescent lights that are more common for interior use on Christmas trees, again selecting the top hit of Amazon.com to serve as our proxy for average and popular wattage. This package comes with 50 bulbs at a power of 20.4 W, or 0.408 W/bulb;
  • Lastly, we’ll look at the efficient LED Christmas lights that an energy-conscious consumer might choose. Going back to Amazon.com to find the most popular basic LED Christmas light (ignoring those with additional energy-using functionalities like timers and light effects), we find this package that comes with 100 bulbs at 4.8 W for 0.048 W/bulb;

For each of these three types of lights, we can use the same basic formula to calculate the total energy use of the Christmas lights over the course of the holiday season:

Referencing our above assumptions, we plug in the number of bulbs as 700, the hours lit per day as 5, and the days lit as 27. Combining those numbers with the Watts/bulb of the three types of lights previously calculated gives the following energy uses:

  • Large incandescent lights: 26,460 Watt-hours (Wh), or 26.4 kilowatt-hours (kWh);
  • Mini incandescent lights: 38,566 Wh, or 38.56 kWh; and
  • LED lights: 4,536 Wh, or 4.54 kWh.

Carbon emissions of Christmas lights

As described in the post about the energy use and CO2 emissions associated with cooking your Thanksgiving turkey, Department of Energy data indicates that 1.096 pounds (or about 0.497 kilograms (kg)) of CO2 are released for every kWh of electricity produced in the United States (on average, this figure varies based on where consumers live and their power providers’ energy mix). Multiplying each of those figures the energy use of each of the light types by 0.497 kg of CO2/kWh gives the following CO2 emissions from lighting the Christmas tree:

  • Large incandescent lights: 13.15 kg of CO2;
  • Mini incandescent lights: 19.17 kg of CO2; and
  • LED lights: 2.26 kg of CO2.

Putting these numbers together with the energy use data gives the following results for lighting the Christmas tree:

Click to enlarge

Carbon emissions from the Christmas tree

In addition, the environmental effects of selecting a Christmas tree are something that we can measure and calculate. In fact, a Montreal-based consulting firm put together a life cycle assessment of artificial vs. natural Christmas trees. This analysis will pull out the final numbers they calculated for CO2 emitted, but the entire report is really worth a read.

The life cycle assessment factors in the average life of each type of tree (natural trees have a lifetime use of one holiday season, while artificial trees are used for six years on average before being replaced), how far people travel to get their trees, the CO2 released when a natural tree is properly burned and recycled, the CO2 absorbed by a natural tree while it’s alive, the land occupation and fertilizers required to grow natural trees, the production of artificial trees, the transport of artificial trees from production (oftentimes overseas)to point-of-sale in North America, and more. In the end, the assessment determined that buying a natural Christmas tree accounts for 3.1 kg of CO2 for the year, while purchasing an artificial tree averages out to 8.0 kg of CO2 per year over the course of its six year lifespan.

Adding the artificial and natural tree CO2 emissions to the previously calculated emissions from lighting gives the following environmental and energy impact of your choice of tree and light types:

Click to enlarge

Note that while it takes energy to produce both a natural and artificial tree, for the sake of this exercise it’s assumed that the effects of that energy use is captured in the CO2 output calculations rather than try to estimate the exact energy use of tree production. Similarly, this analysis only considers the energy used to light the tree and not the energy used or CO2 emitted while manufacturing and transporting the lights, because 1) the information on energy intensity to manufacture and transport the lights is not readily available, and 2) the lights are assumed to be reused over and over again (particularly the LEDs with 25,000 hour bulb life), making the portion of energy to manufacture negligible when distributed over each Christmas season they are used. 



Lighting the Hanukkah Menorah

Basic assumptions

To start off the energy and CO2 calculations for the Menorah, we’ll again start with several basic assumptions:

  • On the first night of Hanukkah, the Shamash (the attendant candle used to kindle the other flames) is lit along with one other light for the duration of the night’s ceremony. On the second night, the Shamash is lit along with two other flames. On the third night, the Shamash and three other lights are lit, and so forth until the eight night when the Shamash and eight other flames are lit.

Energy use of the Hanukkah lights

For the Hanukkah lights, we’ll examine three different lighting options that are widely used to light the menorah– lamps lit with olive oil, traditional paraffin candles, and the increasingly used and environmentally friendly beeswax candles.

Olive oil lamps
While using olive oil lamps, we’ll assume the burning of the Menorah for 30 minutes per night and 90 minutes on Friday night (which is the fourth night of Hanukkah in 2017). Given that a single wick in olive oil will burn through 0.4 and 0.5 ounces of oil per hour, we’ll assume a burn rate of 0.45 ounces per hour per wick. Counting each individual wick that is lit on a given night separately, the total number of burn minutes is calculated as follows:22 wick-hours times 0.45 ounces of olive oil burned per hour gives a total olive oil burned of 9.9 ounces.

The only data point I could find on the energy content of olive oil comes from Wikipedia, giving an average specific energy of olive oil of 39.535 megajoules (MJ) per kg.

Finally then we can calculate the energy of olive oil burned as the following:

But that’s not it– as previously noted there is on Shamash candle that will also be lit each night in order to kindle the other flames. We’ll assume a standard paraffin candle is used as the Shamash for 30 minutes each night (plus an additional 60 minutes on Friday night) for a total of 300 minutes, or 5 hours. Using the standard energy content of paraffin wax of 42.0 kilojoules (kJ) per gram (g) and a standard burn velocity for paraffin wax of 7.5 g/hour, we calculate the energy in the burning of the Shamash candle each night to be the following:

Adding the Shamash tot he olive oil lamps gives a total energy use of about 3.52 kWh.

Paraffin candles
For the energy use of paraffin candles for all eight of the Hanukkah lights plus the Shamash, we simply use the same assumptions used before.

For the 8 candles lit for a cumulative 22 hours over the course of the Festival of Lights:

Add that to the previously calculated 0.44 kWh for the paraffin Shamash candle, and the total energy use is 2.36 kWh.

Beeswax candles
Calculating the energy use by the beeswax candles follows the same process as the paraffin candles. The difference this time is that beeswax, which is more energy-rich than paraffin but burns more slowly, has an energy content of 12.7 kilocalories per gram, or about 53.14 kJ/g (over 26% higher than paraffin candles) and burns at 4.0 g/hour (over 47% more slowly).

Plugging those values into the calculations at a total of 27 wick-hours (22 from the 8 candles and 5 from the beeswax Shamash) gives the following:
Thus, using all beeswax candles corresponds to an energy use of about 1.59 kWh.

Carbon emissions from lighting the Menorah

To determine the total CO2 emissions associated with our three Menorah light options, we already have a total time of burn and a total amount of fuel that is burned and we just need to line those up with the carbon output associated with the fuel types.

Olive oil lamps
Going back to the Wikipedia page on biofuels, we see that the CO2 content of olive oil as a fuel is 14.03 MJ per kg of CO2. Using this we can calculate the CO2 emitted by the olive oil when burned to be the following:

We also need to factor in the CO2 emitted by the Shamash over the eight nights, which we can calculate based on the knowledge (which was discussed in the Jack-O’-Lantern candle burning post) that paraffin candles emit about 10 grams of CO2 for every hour they are burned.

Since the Shamash is burned for 5 hours, this adds 50 grams (0.05 kg) of CO2 to bring the total up to 2.89 kg of CO2 emitted.

Paraffin candles
The data point of 10 grams of CO2 per hour of paraffin candle burned makes this calculation easy. We already established a total cumulative candle burn time (including the eight candles and one Shamash) of 27 hours, so the total CO2 released is 270 g (0.27 kg) of CO2.

Beeswax candles
Lastly, emission calculations for beeswax candles are even easier, as they are generally considered to emit zero CO2. Beeswax candles are touted as the renewable and green candle for just this reason, and while they do literally release CO2 upon their burning, this is CO2 that was recently absorbed by plants in the atmosphere and then transferred to beeswax. In such instances where the path from CO2 absorption to re-release is so traceable and quick, common carbon accounting practice is to count such products as carbon neutral.

Taken together, the energy and environmental impact of how you light a Menorah is given as follows:

Click to enlarge

Note that while the production of the candles and oil uses energy and accounts for CO2 emissions, for the sake of this exercise we’ll assume that the effects of that energy use and CO2 emissions are minimal compared with the energy/CO2 content of the fuel itself, rather than try to estimate the energy use of production and transportation. Similarly, the Menorah that is selected by a family is supposed to be ‘the most beautiful one that is within [their] means,’ up to and including Menorahs made out of silver. Because of this tradition, we can assume that a Menorah is reused year after year, possibly even handed down over generations, and the energy and CO2 emissions associated with creating the Menorah are small enough to ignore due to how small they would be on a per year basis.

Lighting the Kwanzaa Kinara

Basic assumptions and calculations

Last but not least is the lighting of the traditional Kinara for Kwanzaa. Kwanzaa is a seven day celebration that also uses the lighting of candles as a celebratory symbol. The Kinara has seven candles (representing the seven principles of Kwanzaa). In similar fashion to the Hanukkah Menorah, the Kinara starts the first day with one candle lit and then proceeds with two candles the second day, three candles the third day, all the way to lighting all seven candles on the seventh and last day of Kwanzaa.

From my research, it does not appear that there is any minimum or standard amount of time that the candles of the Kinara must be lit as there is with the Hanukkah Menorah. However, as a way of estimating the total burn time I looked at the most popular listings for Kwanzaa candles on Amazon.com. One listing had candles that would have a six to eight hour burn time, while another listed a burn time of five to seven hours. From this information, we can assume that the first candle lit (and thus the one that is lit for all seven nights of Kwanzaa) is expected to burn a total of five hours because the candle in the second listing might not have enough fuel to last longer than that. If this first candle is burned for five hours over the seven nights of Kwanzaa, that implies about 43 minutes of burn time per night.

Multiplying by the number of candles lit each night as we did with the Menorah, we get the following:

These candles can again be made either of paraffin or beeswax. Without going through the step-by-step calculations again (just refer to the Hanukkah calculations for reference), the choice of candles would result in the following energy and CO2 numbers:

Click to enlarge

Note that while the production of the candles and oil uses energy and accounts for CO2 emissions, for the sake of this exercise we’ll assume that the effects of that energy use and CO2 emissions are minimal compared with the energy/CO2 content of the fuel itself, rather than try to estimate the exact energy of candle production and transportation. Similarly to the Menorah, we’ll also assume that a Kinara is going to be reused year after year and as such the energy and CO2 emissions associated with creating the Kinara can be ignored because of how small it would end up on a per year basis.

Comparison

Just because plotting and comparing numbers after all these calculations is interesting and fun, let’s see how the energy use and CO2 emissions of the various options among the three holidays discussed look on a graph:

Click to enlarge

Obviously this graph shows that the Christmas tree comes in (ironically) as the least green among the three holiday decorative centerpieces, which is unsurprising considering its the largest, the one lit the most hours per night and most nights during the season, and the type of fuel required to light it (electricity vs. wax or oil).

If we zoom in on the cluster of Menorahs and Kinaras to get a better view of these options, it looks like this:

Click to enlarge

Even the most sustainable Christmas tree option (using LED lights and a natural tree) come out as less energy- and environmentally-friendly than any of the options of Menorahs and Kinaras. When looking at just Menorahs and Kinaras, olive oil is a less sustainable choice compared with candles, the type of candles make a measurable (though in the end not entirely significant) difference, and, by virtue of needing seven candles instead of nine while lasting only seven days instead of eight, the Kinara ends the holiday season more sustainable than the Menorah.

Conclusion

So what was the point of doing this– should you not put up a Christmas tree or should you not observe the holidays because of the energy implications? Of course not– while these celebrations all have an energy and environmental impact, that’s not a reason to abstain from them. Looking at it all like this is just an interesting exercise. If you do find any of the numbers here alarming, then you can definitely take them to heart and switch to the more environmentally-friendly options– buy natural trees instead of artificial trees, use LED Christmas lights instead of incandescent, or switch from paraffin candles to beeswax candles.

And hey, if any additional use of energy or cause of CO2 emissions nags at you as you sip cocoa by the fire, keep in mind that there is an alternative holiday you can observe that accounts for no energy use or emissions. All you need is a non-decorated aluminum pole and the desire to air your grievances and overcome the feats of strength.

Source

Whatever holiday you observe and however you choose to celebrate– take time to reflect on what the holiday season means, give back to those less fortunate, and share in the joy of being with your family.

Have a happy holiday season!

Sources and additional reading

Beeswax Candles: Alive

Candle Burn Time Calculator

Comparative Life Cycle Assessment (LCA) of Artificial vs. Natural Christmas Tree: ellipsos

Earth Hour 2013: Does It Really Save Energy? CSMonitor

Energy Content of Biofuel: Wikipedia

How Many Christmas Lights for Christmas Trees? 1000Bulbs.com

How Much Does It Cost To Power Your Christmas Lights? Wired

How to Decorate a Christmas Tree: Lowes

How to Light the Menorah: Chabad.org

How to Make Your Own Olive Oil Lamp: Instructables

Lighting the Kwanzaa Kinara: Holidays.net

So, How Much Electricity Do Christmas Lights Use? Christmas Lights Etc.

State Electricity Profiles: Energy Information Administration

The Energy Content of Fuels: University of Virginia

Tips and Tricks for Using Oil Lamps: Preparedness Pro

Trees by Height: Balsam Hill

Weird Questions About Beeswax: Beesource

When Should I Put My Christmas Tree and Decorations Up, When Should I take them Down and When Does Advent Start? The Sun

When Should You Put Up the Christmas Tree? Professor’s House

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Never Tell Me the Watts! Energy and Power Use in the Star Wars Universe

As is quickly becoming my favorite holiday season tradition, a new film in the Star Wars franchise is about to be upon us with the release of Episode VIII- The Last Jedi on December 15! Star Wars has officially been in the cultural consciousness for over 40 years, and as someone who has grown up at any point during those 4 decades, I am a huge fan. Among the many great aspects of a series so long-lasting and deep with rich canonical story-telling, be it through films, books, or video games, is the prevalence of debate it offers for the real-life implications of a fictional universe. Star Wars is the at the pinnacle of such analyses and debates– from economists calculating the cost to build the Death Star (an analysis even cited in an Official White House document) to scientists debating the reality of lightsabers— so it only seems right that this blog dives into the real-life energy implications of various notable Star Wars scenes.

Because Star Wars is so entrenched in pop culture, especially among young boys and girls who eventually become scientists, mathematicians, and engineers, many of these topics have already been explored from academic, scientifically rigorous, and painfully detailed perspective. As such, I chose to allow these crusaders of over-analysis do the digging for me and just cite their work instead of doing the number crunching on my own. Not only would it seem that the hours and immense attention to detail these people have poured into these questions would come to a much close answer to the ‘truth’ than my patience would allow me, but it also allows me to spend my anticipatory re-watch of the entire series without diligent note taking!



So strap in and take a tour of a galaxy far, far away as it relates to energy.

Preliminary notes

A couple important preliminary notes about the calculations cited and used below:

  • Certain questions have been analyzed be numerous people across various fields leading to competing answers to the Star Wars questions. For this exercise, I’m choosing to identify the conclusions that I find to use the greatest scientific rigor and attention to detail, as well as those that show their work and cite their sources. My goal was to find the closest to the ‘true’ answer as possible, but if you find a different number or calculation to be more accurate then I welcome the gloriously nerdy debate in the comment section below!

Source

  • It is also necessary to state that almost every data point going into the below calculations are estimates and approximations. Many of the numbers needed for the calculations simply aren’t provided in the source material, so these mathematical Jedi have resorted to options like determining size of equipment by comparing it to the known size of a human standing adjacent, analyzing the known energy required to melt certain earthen material and assuming the materials in the Star Wars universe are the same or similar materials, or even slowing down clips of the movies to get a frame-by-frame rate of speed.  All that’s to say that the resultant numbers are estimates– diligently arrived-at estimates– but estimates nonetheless that do as good a job as possible at determining the relative order of magnitude. So take them with a grain of salt (which is better than a grain of sand, which is course and rough and irritating, not to mention it gets everywhere).
  • And lastly, with that grain of salt comes another huge one– I know these are movies. They are fictional, the directors often care more about how cool a scene looks instead of how it might break the law of physics, and the small details we analyze were probably not overly scrutinized for adherence to reality. These things don’t matter, but who cares? They are fun to think about and talk about and add depth to one of the greatest sagas in pop culture– so don’t strain yourself thinking too hard about them!

Source

Power required for uses of the Force

Emperor Palpatine’s Force lighting

Description: A number of times throughout the saga, we see Palpatine use his Force lighting, a unique aspect of his Force abilities. In the conclusion of Episode VI- Return of the Jedi, he uses the Force lightning on Luke after Luke once again refuses to join the Emperor on the Dark side and replace Darth Vader as his apprentice (click here for a YouTube link to the scene in question).

Calculation: This calculation is a rather tough one, but we do gain several clues from the scene, as pointed out by Joshua Brown.

The first clue is Luke’s reaction while being struck with the Force lighting, as he is able to call out in a plea for help, and though he is in obvious agony the attack is not fatal. Based on the science of the effect of electricity on the human body, this reaction from Luke would suggest he was experiencing between an AC-3 or AC-4 injury from the Force lighting.  Given the evidence that the longest continuous length of time that Luke was being struck exceeded 10 seconds, the below chart would suggest the current coursing through Luke’s body likely didn’t exceed 30 milliamps (mA).

Source

With the current of the Force lighting in Luke’s body established, the other piece of data we would need is the resistance of Luke’s body– which we can assume is about 100,000 Ohms, the upper limit for the internal resistance of the human body (Luke is a trained Jedi, after all).

Referencing our high school physics textbooks, we’ll remember that power equals current squared times resistance. Plugging in a current of 30 mA and a resistance of 100,000 Ohms gives a Force lighting power of 90 Watts.

Real World Comparison: To put that power in perspective, 90 Watts is about the upper limit for power adapters for Macbook laptops. Surely you don’t want that much electricity coursing through your body, but it’s also an amount of power we routinely carry around in our backpacks.

This amount of power might not seem like much, but watch the scene again and consider whether it truly looked like the Emperor was using all his strength to kill Luke– or was he instead using just a portion of his powers to torture Luke as a message to Luke and/or Darth Vader? It also does end up being a deadly amount of power, as it serves as enough to knock out the electronics of Darth Vader’s life-supporting suit and causes his death.

Darth Vader Force choking and throwing into the ceiling a Rebel trooper

Description: Among the many aspects of Darth Vader that makes him such a menacing presence is his combination of raw power and his tendency to use that power to intimidate those weaker than him. This combination is displayed each time he uses the Force to choke a subordinate or adversary without ever laying a finger on them. This power was on display in the final scene of Rogue One, as he laid waste to a number of Rebel troopers who stood between him and the stolen plans for the Death Star, with one poor trooper being lifted and slammed against the ceiling in a fit of rage (one of the biggest on-screen payoffs in Star Wars films, in my opinion, which can be watched here).

Source

Calculation: Rhett Allain, a physics professor, analyzes this scene for Wired to determine the power of this demonstration of the Force. Allain has to make a couple of assumptions and educated guesses– namely that the Rebel trooper is the size of an average man (1.75 meters tall and 70 kilograms in mass) and that the gravity inside the ship is the same as gravity on Earth at 9.8 Newtons/kilogram.

With that information, Allain then uses a video tracker on the scene to determine that the trooper is lifted up to a height of about 1.5 meters in 0.46 seconds at a constant speed of about 3.3 meters per second.

Time once again to employ the high school physics text book to find that the total work done is calculated as the change in kinetic energy (0.5 times mass times velocity squared) plus the change in potential energy (mass times gravity times height). Plugging in the values listed gives a total work done of 1,410 Joules, which when divided by a time of 0.46 seconds gives the total power output of 3,065 Watts.

Real World Comparison:  To put the power output of 3,065 Watts, or about 3.1 kilowatts (kW), in perspective– consider that 3.1 kW equates to about 4.1 horsepower. Commonly found outboard engines for small motorboats, such as this one, are rated at 4 horsepower as well– so at a moment’s notice Darth Vader is summoning the strength of a small motorboat. While that again doesn’t sound particularly scary, the clip shows the effect that this amount of power output can have when put in the wrong (robotic) hands.

Yoda lifting an X-Wing out of the swamp

Description: In Episode V- The Empire Strikes Back, Luke visits the planet of Dagobah to train with Master Yoda. Seeing the small stature and confusing training tactics, Luke begins to doubt the power of Yoda and question whether he is benefiting at all by being there.

Source

Disappointed by Luke’s insolent attitude and lack of faith in the training process, Yoda provides one of the greatest raw feats of Force strength we’re shown in the films– lifting Luke’s crashed X-Wing ship out of the swamp and into the air using the Force alone (again, the scene in question can be found on a YouTube video).

Calculation: Randall Munroe tackles the question of how much power Yoda outputs in this scene in his ‘What If?’ series. Munroe starts with a series of important assumptions, namely that:

  • The X-Wing is about 12,000 pounds (based on the weight of an F-22 fighter jet and the relative lengths of an F-22 and an X-Wing, Munroe scales the weight of an F-22 down to the proportional weight of the X-Wing), and
  • The gravity on Dagobah is 90% the gravity on Earth (according to sources on the highly detailed, extensive, and canonically accurate website Wookiepeedia).

Munroe then also broke down the video of the scene on a frame-by-frame basis, determining that Yoda lifted the X-Wing to a height of 1.4 meters in 3.6 seconds.

By plugging all these numbers into the equation power = mass times gravity times height divided by time, we find a power output of 19,228 Watts.

Real World Comparison: Sticking with the horsepower comparison, this power of about 19.2 kW equates to about 26 horsepower. What’s the first hit on Google when looking for a vehicle that’s 26 horsepower?

Riding lawnmowers!

Sense in you much fear, do I?

Summary
Click to enlarge

Energy Associated with Star Wars Weapons

Lightsaber

Description: Lightsabers are the first and foremost among weapons you think of when you think of Star Wars, possibly of sci-fi in general. They are weapons mastered by Jedi and replicated by kids everywhere for the last 40 years. Lightsabers really don’t need any introduction, but the scene that is used to calculated the power of a lightsaber possibly does– as our best data points for lightsaber power use come from an early scene in Episode I- The Phantom Menace.

Source

In the scene in question, Qui-Gon Jinn uses his lightsaber to get through a thick, metal door– first he makes a significant cut in the door, and then he sticks his lightsaber into the door for a period of time that allows it to melt a hole in the door (here is a clip of that scene that is for some reason repeated for an entire hour). This quick scene was enough to send Star Wars sleuths to the whiteboards to calculate the power output.

Calculation: For this calculation, we again to look to Rhett Allain at Wired who uses this scene to determine the power needed for a light saber.  This calculation is the most complicated yet, so I would urge you to read the full article to learn more. But in summary, Allain uses the color that the door changes to as it heats up, the dimensions of the cut that Qui-Gon cuts initially,  an assumed set of material characteristics for what this door was likely made out of, and the total time taken to make that cut. Put them all together using equations that would require your graduate-level physics books this time, and you get a power requirement of 28 kilowatts.

Real World Comparison: Rather than looking to the power outputs of an engine, it seemed useful this time to compare this power output to as similar a type of weapon as possible. As it turns out, Lockheed Martin created a laser weapon system for the U.S. Army that is rated at a comparable 30 kW. This Advanced Test High Energy Asset (ATHENA) system has proven capable of shooting down outlaw drones and disabling a truck from a mile away.

Source

Considering the Jedi are carrying around that kind of power in a handheld weapon, you can understand the awe they inspire while expertly and effortlessly wielding lightsabers.

Blaster

Description: While lightsabers get all the buzz, Han Solo is famously quoted as saying that those “ancient weapons are no match for a good blaster at your side.” For the non-Force sensitive players in the Star Wars universe, blasters are the go-to firearm and are thus the most commonly used weapon in the galaxy, according to Wookieeepedia.

Source

To determine the energy of a single blaster bolt, the team at Ebates analyzed an escape scene in Episode IV- A New Hope where Princess Leia takes a blaster and shoots a hole through a metal grate for her, Luke, Han, and Chewbacca to crawl through. Not only does Leia succeed in winning the audiences heart by showing that this Princess is no damsel in distress (toward the end of this YouTube clip), but she also gives us the evidence needed to estimate the destructive energy of a single blaster bolt.

Calculation: According to the numbers crunched by eBates, the shot with the blaster created a hole about 3 feet in diameter in the metal grate, seemingly by vaporizing the metal.  Estimating the dimensions and density of the metal that was vaporized (about 54 kilograms) and knowing the energy needed to vaporize a kilogram of iron (6.34 Megajoules) leads to a rough conclusion that the blaster shot yeilded about 342 Megajoules.

Real World Comparison: Because the result of the blaster bolt here appeared to be a literal ‘blast’ of energy, it would be useful to know what would be required to yield the same explosive blast in the real world. Luckily, a unit of such destructive energy is standardized by the gram of TNT and is directly convertible to and from joules (one kilogram of TNT yields 4.184 Megajoules).  Thus for our lovely Princess to have blasted through the iron gate with the same energy of the blaster, it would have required about 82 kilograms of TNT.

Star Destroyer’s turbolaser

Description: The devoted fans at StarDestroyer.net took on the question of the energy from a shot by the empire’s domineering Star Destroyers.  In terms of military might (outside of the megaweapons to be discussed next), the Star Destroyer certainly stands as one of the most intimidating shows of military force in any galactic fleet.

Source

In one particular scene of Episode V- The Empire Strikes Back, a single blast from the turbolaser of the Star Destroyer is shown to clear asteroids right from its path. This show of firepower gives us a good idea of exactly how much destructive energy is contained in these blasts (watch in action in this YouTube clip).

Calculation: This calculation is another fairly in-depth and complicated one, so I would again recommend reading their entire write-up of the topic in full. However, the basic gist is that one bolt was able to instantaneously melt an asteroid (composed of the average asteroid composition) that measured on the order of 20 meters in diameter. Knowing the science behind the melting of such an asteroid leads to the calculation that the energy in a single turbolaser blast is 30 Terajoules or 30 million Megajoules.

Real World Comparison: A single shot of the Star Destroyer’s turbolaser has the destructive energy of 30 terajoules, which for context is about half the total energy released by the bomb dropped on Hiroshima to end World War II. Given that the Star Destroyer was releasing dozens of these shots over the course of its chase of the Millenium Falcon, you would understand why those being pursued might ‘have a bad feeling about this.’

Original Death Star’s superlaser

Description: The Death Star is the Ultimate Weapon of the Empire, the presence of which alone was enough to inspire fear and garner compliance from every corner of the galaxy. That fear is well-deserved because this awe-inspiring weapon was created to have the power to completely destroy planets.

Source

That’s not some sort of hyperbole, as we saw in the scene of Episode IV- A New Hope when the Empire demonstrates the power and unleashes the Death Star to destroy Princess Leia’s home planet of Alderaan. This show of force gives us the information we need to estimate how much destructive power is unleashed with the superlaser of the Death Star (watch the clip here, trigger warning for anyone who may have had friends or family on the planet formerly known as Alderaan).

Calculation:  Our friends at StarDestroyer.net also did the analysis on how much firepower was behind this blast from the Death Star. These calculations might be the most scientifically detailed yet, so definitely check out the full analysis. In the end, they used three different methods to estimate the energy of the weapon (calculating the surface escape velocity that would be required for planetary destruction, the constant gravitational binding energy that would need to be overcome, and the variable gravitational binding energy that would need to be overcome). Each of these calculation methods resulted in a final figure betweeen 2.2 x 10^32 and 3.7 x 10^32 joules. This range is a wide one in terms of an exact answer, but they are all in the same order of magnitude and thus inspire confidence in their approximate accuracy. For the sake of argument, we’ll go right in the middle and assume the energy of the Death Star is 3 x 10^32 joules, or 3 x 10^26 Megajoules.

Real World Comparison: We’re up at a level of energy that doesn’t have any real Earthly comparisons, as the total annual world energy consumption is on the order of 10^14 Megajoules– many orders of magnitude less than a single shot from the Death Star.

Instead we have to go, rather appropriately, into space. The 3 x 10^26 Megajoules of energy used to destroy Alderaan is equivalent to the total energy output of the Sun over the course of about 9 days.

Starkiller Base’s superweapon

Description; In the first film of the latest Star Wars trilogy, Episode VII- The Force Awakens, the Death Star gets completely outclassed as a weapon. The First Order takes the idea of a planet-sized battle station capable of wiping out a planet and inspiring fear-based obedience and cranks it up to 11, as their Starkiller Base is a superweapon built into a mobile planet that is capable of wiping out an entire star system.

 Source

In this scene that shows the first ever shot from the superweapon, the massive scale of the destructive energy being unleashed is evident and is used to wipe out five planets like they were never there– something never before seen in the Star Wars universe. The energy needed for this weapon is literally siphoned from the energy/plasma of a nearby star and then unleashing it in one blast. As you can imagine, this amount of energy is almost unthinkable.

Calculation: Jason Haraldsen, a physics professor, tackles the science behind Starkiller Base in a piece he wrote from the Huffington Post. Despite his conclusions that there are a number of aspects of Starkiller base that would be scientifically impossible (for one, Starkiller Base and its weapon are hosted on an ice planet– yet the harvesting of energy directly from a star does not end up overheating the planet or even melting the snow on it?) Haraldsen calculates the amount of energy that is needed to charge up the superweapon by converting the mass of the nearby star into pure energy. Keeping things way oversimplified, just converting the mass of the star to energy using E = mc^2 results in an energy output of 2 x 10^41 Megajoules.

Real World Comparison: If the Death Star’s energy required us to go from the Earth to the Solar System, Starkiller Base forces us to go on a galactic scale to find an energy equivalent. The 2 x 10^41 Megajoules of Starkiller Base’s superweapon is equivalent to the energy released by 1,000 supernovas. Talk about unlimited power!

Summary

Click to enlarge

Conclusion

Do the filmmakers put as much attention into the minute details as we fans do in splicing apart and analyzing those details? Probably not. But that’s fine because the debate can be fun and educational and open up our eyes a bit about the comparable calculations in the real world. While thankfully it seems unlikely that any ill-intended human will create a sinister weapon as destructive as the Death Star or Starkiller Base, let us not forget that sci-fi can and has influenced the imaginations in the real world– from President Reagan’s Star Wars missile defense initiative to the ever-increasing presence of droid-like robots in our life.  So pay attention to any new inventions while you’re watching The Last Jedi, and let me know in the comments if you have any other Star Wars (or pop culture in general) energy-related questions you’d like to read about next!

Sources and additional reading

Ask Us: NASA

BP Statistical Review of World Energy

Death Star Firepower: StarDestroyer.net

How Many Batteries Would It Take to Power a Lightsaber? Or the Death Star? infographic journal

How strong is the Emperor’s lightning attack?

In Which We Literally Calculate the Power of the Force: Wired

Lockheed Martin’s laser weapon takes down 5 drones in live-fire demonstration: New Atlas

Power Source for a Lightsaber: Wired

Supernovae: Hyperphysics

The Physics Behind the Starkiller Base in Star Wars: The Force Awakens: Huffington Post

Turbolaser Firepower: StarDestroyer.net

US Army gets world record-setting 60-kW laser: DefenseNews

What was the yield of the Hiroshima bomb? Warbird Forum

Worker Deaths by Electrocution: NIOSH

Yoda: What if?

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Deconstructing Units of Energy into Pizza, Fly Push Ups, and Grenades

When looking at energy use in everyday life situations, it is easy to overlook what the units used actually mean. When getting the electric bill in the mail, most people will simply compare the kilowatt-hours from last month to this month and note if their bill has gone up or down. When buying a new energy-efficient dryer, you know the fewer watts used the less energy it will be. The same mental comparisons are used all the time by people who do not have to deal with energy extensively– such as with the horsepower of a car or the calories in a sandwich.

However, it is all too common for people to forget the real significance of and differences between various units of measure related to energy and power use once they pass their high school physics class. Newscasters will constantly use kilowatts and kilowatt-hours as if they’re interchangeable (they’re not). Writers will misrepresent statistics online as if the difference between megawatts and gigawatts are not massive (they are).



For those of us that work in the energy industry, these numbers are much more tangible and easy to understand. However that does not describe a majority of citizens who are having these statistics thrown at them all the time, so this article will serve as a reference and allow you to re-up your energy statistics literacy.

The Basics

Energy vs. Power

The cardinal sin when dealing with energy units is confusing energy and power, a mistake that is unfortunately one of the most common as well. Even in mainstream news articles, it is not uncommon to see the total energy used for something to be listed in watts or vice versa (e.g., this article quotes the rate of energy use of a soccer stadium in kilowatts per hour, which you will shortly understand to be nonsensical if taken literally). So clearing up the confusion here is top priority.

The technical definitions of energy and power, according to the Energy Information Administration (EIA), are as follows:

Energy: The capacity for doing work as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy)

Power: The rate of producing, transferring, or using energy, most commonly associated with electricity

Put simply, energy is the total work that is done while power is the rate at which that work is done. This concept can still be a bit tricky, so the easiest way to keep it straight is through metaphors. As one example, you can think of the relationship between energy and power as water flowing from a hose to a bucket. The volume of water that has been added to the bucket at any given point is comparable to the total energy use, while the rate that the water is flowing from the hose into the bucket can be considered the power. Another useful metaphor is to consider power to be the speed a car travels along a highway, while the total distance traveled would be the total energy. The main point is to think of power as a rate that is occurring with time (gallons of water per second, miles per hour) while the energy can then be thought of as that rate multiplied by the amount of time to get the total quantity (gallons of water per second times total seconds = total gallons of water, miles per hour times total hours = total miles driven).

To bring it to real world applications of energy and power, think of a light bulb in the lamp of your living room. The light bulb might be rated at 60 Watts, which is the power rating. 60 Watts is the rate of energy use of the bulb, and if you leave it operating for 2 hours then the total energy use is 60 Watts times 2 hours or 120 Watt-hours. Watt-hours, often divided by 1,000 to be expressed in kilowatt-hours, are the total energy use you will see come up on your monthly power bill (for more real-world applications of power and energy calculations, see the recent blog post on the energy used in various Thanksgiving turkey cooking methods).

Once you understand the difference between energy and power, you will start to see them used improperly all too often.

SI units vs. Imperial units vs. every other type of unit

To anyone who has to deal with the variety of units available to measure the same quantity, it can seem very confusing and unnecessary. Certainly it would be easier if everything and everyone used the same units and no conversion was needed. Unfortunately, that is not the world we live in for a variety of reasons– everyone has seen or heard how hard it has been to try to get the metric system adopted in the United States.

The reality is that there are many different units because these units originated at different times, by different people/industries, for different uses. The development of the metric system during the French Revolution was the first attempt to create internationally agreed upon units. Prior to that time, the world was a much larger place and it was not uncommon for units that even carried the same name to vary in actual measurement depending on where you were and who you asked. As science and trade expanded with the ever-shrinking global stage, units became more and more standardized until the International System of Units (SI) was created in the mid-20th century. These units are standard and widely accepted across the scientific landscape, no small victory for unit standardization.

Even with that success, however, many industries were already set in their way. For example, even though the automotive industry could use the widely accepted wattage to describe the power of an engine, people already understood horsepower in the context of a car. Because of the inertia and history of units like this, the implementation of the SI system did not take off in all sectors. While this may have been the easiest choice for those industries, it leaves the layperson with an alphabet soup of units and abbreviations to wrap their head around. Hopefully this article will do a small part to clearing that all up.

Prefixes

Another important part of the tangled web of units, particularly among SI and metric units, is the use of standard prefixes. Prefixes are used to take a standard unit and modify it by a power of ten. A familiar example would be the difference between a meter and a kilometer. Kilo- is the standard prefix for a multiplier of 10^3 or 1,000, which is why a kilometer equals 1,000 meters. These types of prefixes, summarized in the table below, can be applied across all sorts of units and the meaning is always the same– look at the power of ten multiplier and apply it to the unit.

The prefixes at the extreme of either end (such as yotta- and yocto-) are rarely used because they are so large/small that they are not needed to describe real, tangible energy/power quantities you’ll come across. The ones that are commonly used include giga-, mega-, kilo-, milli-, and micro-, and in fact some of the units described in the below tables will have those prefixes because the power-of-ten-adjusted units are more commonly used in certain applications than their base units.

Units to know

Energy

With all that background out of the way, we can look at 24 various units used to measure energy. Some of these are more common and will be familiar to most people, others are more niche and relate to specific industries or fields of study, while others still are rarely used but are still interesting to consider. Again keep in mind you may run across more units made up of the measures below combined with one of the prefixes above– simply use the prefix multiplier to modify the designated unit in the below table.

This first table will list these energy-measuring units, from smallest to largest, along with the manner in which they are typically used, the qualitative fundamental equivalence by definition, and the standard quantitative reference.

Table 2: Units of Energy Across Industries and Applications

UnitAbbreviationTypical useFundamental equivalenceStandard Reference
electronvolteVUsed by astronomers to measure energy of electromagnetic radiation, as well as to describe the difference in atomic/molecular energy states.

Also used by particle physicists to measure mass (based on E=mc 2 )
Amount of energy one electron acquires from accelerating through one volt1.602 x 10^ -19 Joules
RydbergRyUsed by chemists and physicists to claculate the energy levels in that are absorbed or emitted as photons as electrons move between energy levels of a hydrogen atomGround-state energy of an electron in the Bohr model for the hydrogen atom13.605693009 eV
HartreeEhUsed in calculating energy of molecular orbitsThe electic potential energy of the hydrogen atom in ground state (and thus double E h )27.211 eV
ergergNot commonly used today, but can still be found in old European scientific papersAmout of energy used when a force of one dyne is exerted over one centimeter 100 nanojoules
jouleJUsed in electricity, mechanics, thermal energy, and other basic sciences on a small scaleAmount of energy transferred to an object when a force of one newton acts on the object in the direction of its motion through a distance of one meter (i.e., one Newton-meter)As the SI unit of measurment for energy, considered the base use unit of all energy and is the common reference for other units of energy
foot-pound forceft*lbUsed to describe muzzle energy of a bullet in small arms ballistsAmount of energy transferred to an object when applying one pound of force over a distance of one foot1.35581795 Joules
thermochemical calorie**cal thUsed in chemistry to describe the energy released in a chemical reactionAmount of heat/energy needed to raise the temperature of 1 gram of water 1 o C (at 17 o C)4.8140 Joules
gram calorie**calUsed in chemistry to describe the energy released in a chemical reactionAmount of heat/energy needed to raise the temperature of 1 gram of water 1 o C (from 14.5 to 15.5 o C)4.8155 Joules
British thermal unitBTUUsed as a common unit of energy content by industry and analysts to compare energy sources or fuels on an equal basisAmount of heat/energy needed to raise the temperature of one pound of water by 1 o F1,055 Joules
Watt-hourWhUsed commonly in electrical applications Amout of energy used when one Watt of power is expended for one hour3,600 Joules
food Calorie, or kilocalorie**kcalIn common practice, nutritional calories are referring to these kilocalories (or Calorie, capitalized) as a means to measure the relative heating/metabolizing energy contained within a foodAmount of heat/energy needed to raise the temperature of 1 kilogram of water 1 o C (from 14.5 to 15.5 o C)1,000 thermochemical calories
gram of TNTg of TNTUsed to compare the relative size of explosions based on their release of energyAmout of energy in the explosive yield of one gram of Trinitrotoluene (TNT)4,184 Joules
(The real use of a gram of TNT would result in a range of energy outputs between about 2,700 and 6,700 Joules, so the actual conversion was somewhat arbitrarily defined as 4,184 Joules or exactly 1 kilocalorie)
megajoulesMJUsed to describe the energy content of liquefied petroleum gas (LPG) and natural gas in the context of gas heaters in buildingsOne million times the amount of energy transferred to an object when a force of one Newton acts on the object in the direction of its motion through a distance of one meter (i.e., one Newton-meter)1.0 million Joules
horse-power hourhphUsed in railroad industry to describe a performance-use basis when companies lend locomotives to others (e.g., Railroad A lent Railroad B a 4,000 horsepower locomotive to use for 2 hours, Railroad B now owes Railroad A a payback favor of 8,000 horsepower-hours)Amount of work that can be done (or energy that can be expended) by a horse over one hour2.686 x 10^6 Joules
kilowatt-hourkWhThe common unit of measure used as a billing unit for electricity delivered to consumersAmount of energy if a constant power of one kilowatt is transmitted for one hour3.6 x 10^6 Joules
kilogram of hard coalkg of hard coalUsed within the coal industry to compare the energy output of other fuel types to the output of a standard measure of coalAmount of energy emitted when burning one kilogram of coal7,000 kilocalories
ThermthmUsed by natural gas companies to convert volume of gases to its equivalent ability to heatAmount of heat energy from burning 100 cubic feet of natural gas100,000 BTU
gasoline gallon equivalentGGEUsed to compare the cost of gasoline with other fuels that are sold in different units for internal combustion enginesAmout of energy equivalent to that found in one liquid gallon of gasoline5.660 pounds of natural gas
gigajoulesGJUsed on a global scale to compare the amount of energy used by different nations over given time periodsOne billion times the amount of energy transferred to an object when a force of one Newton acts on the object in the direction of its motion through a distance of one meter (i.e., one Newton-meter)1.0 billion Joules
ton of TNTton of TNTUsed to describe the energy released in an explosionAmount of energy released in the detonation of a metric ton of TNT4.184 Gigajoules
barrels of oil equivalentBOEUsed by oil and natural gas companies (and analysts of those industries) that have access to both fuel types to describe the overall energy content of their reserves in a simple, single numberAmount of energy equivalent to that found in a barrel of crude oil (42 gallons); for natural gas, the conversion is to about 6,000 cubic feet of natural gas5.8 million BTU*
Ton of coal equivalentTCEUsed to describe very large amounts of energy output on a national or global scale with coal as the reference pointAmount of energy generated from burning one metric ton of coal0.697 tonne of oil equivalent (according to World Coal Association)
0.700 tonne of oil equivalent (according to International Energy Agency)
tonne of oil equivalentTOEUsed to describe very large amounts of oil or natural gas, either in terms of trade and transportation or natural production/consumptionAmount of energy equivalent to that found in one tonne (i.e., a metric ton, or 1,000 kilograms) of crude oil7.33 BOE (according to SPE)
41.868 GJ (according to OECD)
10.0 kcal (according to IEA)*
quadquadUsed by the Department of Energy and others in the field to discuss the total energy production and use across the globeEqual to exactly 10 15 BTU, i.e., one quadrillion BTU (quad for short)1,000,000,000,000,000 BTU

*These values are approximate because different grades of oil/gas have slightly different energy equivalents, and thus different agencies/bodies sometimes use slightly different measures of them.

**It’s important to note the difference between calories and Calories– Calories with a capital C are the nutrtional Calories everyone is familiar with counting on diets. These Calories are actually known as kilocalories and are 1000 thermonuclear calories, so do not mix up Calories and calories…

To make some more sense of this array of units, both massively large and incomprehensibly small, the following table puts the units into some more context. In this table, you’ll find a real-world example of what can be done with a single unit of that energy measurement, how many Joules it equates to for comparison’s sake, and the multiplier needed to get from the previous unit of energy to that one.

Click to enlarge

Power

The same exercise can be done for units of power (or rate of energy over time), as there are just as many different units for various industries, applications, and technical necessities. For power, we’ll focus on 17 of the more commonly used units– though remember you might come across all of them modified by the previously discussed prefixes.

Again, this first table will list all the power-measuring units, from smallest to largest, along with the manner in which they are typically used, the qualitative fundamental equivalence by definition, and the standard quantitative reference.

Table 4: Units of Power Across Industries and Applications

UnitAbbreviationTypical useFundamental equivalenceStandard Reference
erg per seconderg/sNot commonly used today, but in old scientific papers could be used to express power on an atomic scaleAmout of power used when a force of one dyne is exerted over one centimeter in one second100 nanowatts
milliwattmWUsed to measure the power needed by very small electrical components, such as small lasers to read CDsEqual to one thousandth of a Joule per second, or the work/power needed to hold an object's velocity constant at one meter per second against a constant force of one thousandth of a Newton0.001 Watts
dBmdBmUsed as a measure of power in wires in radio, microwave, and fiber-optic networksdBm is measured as the decibals relative to one milliwatt on a logarithmic scale, where the dBm of a power P in millwatts equals 10 x log(P)Not applicable because of the log-based scale. While 1 dBm is about 1.3 milliwatts, 50 dBm is 100 Watts and -50 dBm is 10 nanowatts.
Foot-pounds per minuteft*lb/minCommonly used as a mesaure of power in the foot-pound-second (FPS) unit system, which was the most common scientific unit system in English publications until the mid-1900s. The work done to apply a force of one pound-force over a linear dispalcement of one foot over the course of a minuteConsidered the base use unit for power in the FPS system, others reference the foot-pound per minute
kilowatt-hour per yearkWh/yEnergy consumption of some household appliances is often expressed based on the kilowatt-hours used over the course of a year given certain assumptions (kWh/y of a washing machine based on 180 standard cleaning cycles). While this may appear to be an energy unit and not a power unit, the time component of hour of kWh and the year cancel out to leave you with a measure of power-- which is what this measure really is, an understandable way to compare the power rating of various appliances Based on the assumptions given by the particular appliance label, each additional kWh/y is another expected kilowatt-hour to show up on your power bill over the course of an entire year with typical appliance use1 kilowatt-hour per year divided by 8,760 hours per year, or about 0.114 Watts
British Thermal Units per hourBTU/hOften used as the power rating for furnaces and other large heating systemsAmount of power needed to raise the temperature of one pound of water by 1 o F over the course of an hour1,055 BTU/hr divided by 3,600 seconds/hr, or 1055/3600 Joule/second which equals about 0.293 Watts
WattWUsed as the basic measurement of electrical power in small household-sized applicationsEqual to one Joule of energy per second, or the work/power needed to hold an object's velocity constant at one meter per second against a constant force of one NewtonAs the SI unit of measurement for power, considered the base use unit of all power and is the common reference for other units of power
kilocalories per hourkcal/hUsed to measure the metabolic rate of the human body, that is the amount of Calories your body will burn per hour doing various activities (e.g, exercising, sleeping, etc.)The amount of work needed to increase the temperature of one liter of water by 1 o C over the course of an hour1,000 calories per hour
calories per secondcal/sUsed by chemists when describing the rate of heat/energy transfer in chemical reactionsAmount of power needed to raise the temperature of 1 gram of water 1 o C (at 17 o C) over the course of 1 second4.184 Watts
Metric horsepowerPSUsed for advertising in the same applications as mechanical horsepower but in countries who use the metric system (often leading to confusion and mixing up the units, though the official horsepower ratings of engines are typically conservative enough that it's not overpromising power0Equal to the power required to raise a mass of 75 kilograms over a distance of one meter in one second75 kilogram*meters per second
Mechanical HorsepowerhpUsed to measure the output shaft of an engine, turbine, or motor in applications from cars and trucks down to chain saws and vacuum cleanersWhen invented by James Watt (inventor of the steam engine), it was derived by calculating the average work a pony at a coal mine could do in a minute and then increasing that by 50 percent33,000 foot pounds per minute
Electrical horsepowerhp(E)Used in the United States for the nameplace power output capacity of electrical motorsIntended to be equivalent in use to the mechanical horsepower, but is defined as exactly 746 Watts746 Watts
kilowattkWTypically used to describe power output of engines, motors, and other machinery. The work done to apply a force of one thousand pounds-force over a linear dispalcement of one foot over the course of a minute1,000 Watts
Tons of refrigerationTRUsed to rate the power of commercial refrigeration systemsThe power needed to freeze a short ton of water at 0 o Cover a 24 hour period12,000 BTU/hr
Boiler horsepowerhp(S)Used to denote a boiler's capacity to deliver steam to a steam engineEqual to the thermal energy rate required to evaporate 34.5 pounds of fresh water at 212 o F in one hour33,475 BTU/h
megawattMWUsed to describe the power used by very large electical equipment and vehicles, such as warships, super colliders, electric trains, or large commercial buildingsThe work done to apply a force of one million pounds-force over a linear dispalcement of one foot over the course of a minute1,000,000 Watts
gigawattGWDenotes the power output of large power plants and electrical capacity on a national scaleThe work done to apply a force of one billion pounds-force over a linear dispalcement of one foot over the course of a minute1,000,000,000 Watts

Again, a useful way to make sense of all these power units is to give them more meaningful context. The next table shows some of the real world examples of these different levels of power output, converts them all to Watts for the sake of comparison, and the multiplier between two consecutive units.

Click to enlarge

Conclusion

Armed with the knowledge of these units of energy and power, you’ll be well prepared to tackle statistics anew– you’ll have useful context for how much energy was in the recent 5,000 barrel oil spill on the Keystone Pipeline (using the above information, we can calculate that 5,000 barrels of oil is over 30,000 Gigajoules– or equivalent to the average annual electricity consumption of over 700 American households), or you’ll also have not so useful (but fun!) context for the energy content of a gallon of gasoline (the same as over 127 slices of large cheese pizza or 30 kg of TNT).  Either way, being literate in your scientific and energy-related units will make you a more informed consumer of the news– if only everyone editing the news could do the same and stop using ‘Watts per hour’!

Sources and additional reading

A Megajoule or MJ Probably Isn’t What You Think: Elgas

Aqua-calc: Conversions and Calculations

Arkansas State Energy Profile: Energy Information Administration

Ask Trains from December 2007: Trains Magazine

Atomic Units: Nature

Barrel of Oil Equivalent: Investopedia

Blast effects of external explosions: Isabelle Sochet

Bluetooth range and Power: Electronics Stack

Brief history of the SI: National Institute of Standards and Technology

British Thermal Units (BTU): Energy Information Administration

By gum! Chewing to power your hearing aid: CNBC

Calorie: Encyclopedia Britannica

Choose the right charger and power your gadgets properly: Wired

Coal conversion statistics: World Coal

Coal equivalent: European Nuclear Society

CODATA Recommended Values of the Fundamental Physical Constraints

Conversion factors: Organization of Petroleum Exporting Countries

Electron Volt: Universe Today 

Elephants: San Diego Zoo

Energies in Electron Volts: Hyper Physics

Energy Conversion Calculators: Energy Information Administration

Energy Examples: Genesis Now

Energy Units: APS Physics

Energy Units and Conversions: Dennis Silverman

erg: WhatIs.com

Eu Energy Labels: What does kWh/Annum mean?

Exploding Laptop Batteries

Foot-Pound Force Per Minute: eFunda

Frequently Asked Questions: Energy Information Administration

Glossary: Energy Information Administration

Horsepower-hour: Collins Dictionary

Horsepower: Encyclopedia Britannica

How Hard Does It Hit? Jim Taylor

How Horsepower Works

How Many Calories Are Burned By Coughing? LiveStrong

How Many Calories Do You Burn Doing Everyday Activities?

How Many Flies Would It Take To Pull A Car? Neatorama

How much electricity does a solar panel produce? Solar Power Rocks

How much energy do my household appliances use? Energy Guide

Is it really worth my time to eat that last grain of rice?

Joule: techopedia

Launching satellites: Science Learning Hub

Measuring energy: IEEE 

Metric Conversions

Nanotechnology Introduction: Nanotechnology Now

NIST Guide to the SI: National Institute of Standards and Technology

Nonconventional Source Fuel Credit

One Calorie is Equivalent to One Gram of TNT In Terms of Energy: Today I Found Out

Papa John’s Nutritional Calculator

Physical Phenomena: University of Sydney

Physlink

Projectiles, Kinetic/Muzzle Energy and Stopping Power

Report of the British Association for the Advancement of Science

Rydberg: Wolfram Research

Rydberg Constant: National Institute of  Standards and Technology

Rydberg Unit of Energy: Energy Wave Theory

The Adoption of Joules as Units of Energy: FAO

Tonne of coal equivalent: Business Dictionary

Tonne of oil equivalent: Organization for Economic Cooperation and Development

Turning sweat into watts: IEEE

Understanding Energy Units: Green Building Advisor

Unit Conversion Factors: Society of Petroleum Engineers

Unit converter: International Energy Agency

USB Flash Drives: AnandTech

watt-hour (Wh): WhatIs.com

What’s a hartree? National Institute of Standards and Technology

What is a Joule? Universe Today

What is a GJ? Natural Resources Canada

What is a Ton of Refrigeration: Power Knot

What is a Watt, Anyway? Building Green

What is a Watt Hour? SolarLife

What is resting metabolic rate?

Why Do We Use a Dumb Unit to Measure Explosions? Gizmodo

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.  

Talking Turkey: Thanksgiving Dinner Energy Use and Carbon Dioxide Emissions

Thanksgiving is one of the most wonderful time of the year, when families gather and spend time together while the smell of turkey seeps in from the other room. You’ve probably never given much thought to the energy use or environmental impact behind that intoxicating turkey smell coming from the kitchen, and in fact the country’s overall energy use drops on Thanksgiving because the increase in kitchen power use is offset by the drop in energy use from office and commercial buildings that are closed for the holiday.

However it’s always interesting to look at the actual energy numbers behind various regular activities and consider if there’s a way to do it better. Especially these days when online cooking forums and the Food Network is constantly making it trendy to cook your Thanksgiving turkey in new and novel ways. Your grandmother’s recipe isn’t the only one in town anymore (though I’m sure it’s still the best). Those cooking the turkey now have deep fryers and smokers, while Turducken is being eaten by NFL players after the Thanksgiving Day games.



With so many new cooking methods for Thanksgiving dinner, it got me to wonder what the energy cost was to cook turkey using these different methods. While there were investigations on the total energy use across the country to cook Thanksgiving dinner (linked later in this article), I could not find anything about the energy cost or associated carbon dioxide (CO2) emissions of an individual turkey cooked using different methods, so I thought I’d run through them myself!

Recipes

After searching across the Internet, I settled on seven different methods to cook your Thanksgiving turkey– the traditional roasting of a turkey and six newer and trendier options that the hip or contrarian chef might utilize. These seven methods are the following:
  • Roasting;
  • Braising;
  • Deep frying;
  • Grilling;
  • Smoking;
  • Spatchcocking; and
  • Sous vide.

For each of these cooking methods, I’ve sought out a recipe either from a well-known chef of repute or directly from the manufacturer of the turkey or the cooking apparatus in question. By using these recipes, ideally these authorities will have an air of authority to them. Because each recipe offers cooking times based on various size turkeys, this analysis will normalize each recipe for a standard 15 pound (lb) turkey as the size recommended for a dinner of 12 people.

If you want to skip the details of the recipes and the calculations, click here to go straight to the results!
 
Note: For all of the below recipes, there are additional energy consuming steps that are not going to be included in the calculations. These steps include removing turkey from the oven to baste, pre-refrigeration, sauteing after the turkey is fully cooked to get crispy skin, etc. The point is the calculations below will focus on the energy needed to fully and safely cook the turkey, and any energy used before or after that process will be ignored for simplicity and uniformity. Of course you will be making side dishes and putting on finishing touches, so your mileage WILL vary compared with what is calculated here. The goal of this exercise is just to get a back-of-the-envelope approximation for how the different cooking methods affect the energy required– they are definitely not going to be exact or completely robust. You’ve been warned! 

Roasted turkey

Since this is the traditional cooking method, it seemed criminal to use a recipe other than the one championed by Julia Childs. Her traditional recipe for a 10 to 13 pound turkey calls for the oven to be preheat to 450oF and then the turkey roasted for 30 minutes before reducing the oven to 350oF and roasting for another 2 to 2 hours 30 minutes.
Normalizing for a 15 lb turkey, we’ll use the higher time estimate and add 15 minutes for the extra weight and say the turkey will be cooked in the oven for 3 hours 15 minutes.

Braised turkey

 Braised turkey is a great segue from the traditional to the more novel turkey-cooking methods, as it doesn’t stray too far from the original whole turkey roasting method. You are still cooking the turkey fully in the oven, but with the main difference that the turkey is sitting in a pan of vegetables and stock to bring in more moisture to your turkey.

For the braised turkey, we’ll stay with household names and use Bobby Flay’s recipe for herb roasted and braised turkey. This recipe calls for an oven preheated to 450oF with the 17 pound turkey and a bed of vegetables cooked for 45 minutes before the temperature is reduced to 350oF and cooked an additional 2 to 2 hours 15 minutes longer (while basting with warm chicken stock). After the whole bird is cooked, the legs are removed and braised in a roasting pan with stock for an additional 1 hour at 350oF.

To normalize to a 15 pound turkey, we’ll say the braised turkey cooks in the oven for a total estimated cook time of 3 hours 30 minutes.

Deep fried turkey

If you can manage to get it done without an explosion or trip to the hospital, deep frying turkey has become one of the more exciting and talked about cooking alternatives. Bobby Flay’s colleague at Food Network, Alton Brown, has one of the most used deep fried turkey recipes for those who love the science and Internet-trends of cooking.

For a 13 to 14 pound turkey, Alton has you heat up a 28 to 30-quart pot of oil to 250oF, add in the turkey and raise the temperature to 350oF, and once at that temperature cooking for 35 minutes.

To account for the weight of a 15 pound turkey, we’ll say this recipe cooks with a propane heater for a total of 40 minutes.

Grilled turkey

The grilled turkey recipe chosen comes straight from Butterball, the turkey supplier that accounts for 20 percent of total turkey production in the United States. Among grilling aficionados, the debate to grill by charcoal or by gas is one of the most heated. In addition to differences in taste, ease, and convenience, the choice of grill type also affects the end energy use to cook. Luckily for us, Butterball provides instructions for both a charcoal and gas grill.

Butterball’s recipe for charcoal grilling says that the 10 to 16 pound turkey will be cooked over 50 to 60 charcoal briquettes (after those initial briquettes have been burned for 30 minutes). At that point, the turkey is to be placed on the grill for 2 to 3 hours, with 12 to 16 briquettes being added every 45 minutes to 1 hour. To normalize at the 15 pound turkey, we’ll estimate that initially 60 charcoal briquettes will be used and, during the cooking process, 50 more briquettes will be added for a total cooking fuel of 110 charcoal briquettes on a charcoal grill over the course of 3 hours.

Butterball’s recipe for gas grilling says the same 10 to 16 pound turkey is cooked over indirect heat (after 10 to 15 minutes of preheating) at 350oF for 2 to 3 hours. For the 15 pound turkey we’ll assume the turkey is cooked on a gas grill at 350oF for the whole 3 hours.

Smoked turkey

Where deep frying or grilling the turkey may have once held the title as the ‘macho’ way to prepare a Thanksgiving turkey (whatever that may mean), smoking the meat might just have taken that crown. Using lower heat over longer periods of time, smoking turkey evokes the expert barbecue pit masters of the country to impart full flavor without drying out the turkey. Butterball once again provides authoritative guidance to smoking your Thanksgiving dinner, again allowing the consideration of two different fuel types.

Butterball’s recipe for preparing a turkey in a water smoker uses 10 pounds of charcoal briquettes (pre-burned for 30 minutes) to start the cooking process, adding in 12 to 14 more charcoal briquettes every 1 hour 30 minutes to ensure the temperature remains at 250oF through a total cooking time of 6 to 10 hours for a 12 to 18 pound turkey. For our 15 pound turkey, we’ll call that cooking fuel of 10 pounds plus 70 briquettes of charcoal over a cooking time of 8 hours in the water smoker.

When using an electric smoker, Butterball’s recipe calls for the smoker to be set at 225oF and the 8 to 18 pound turkey to be cooked for 8 to 12 hours. Normalizing to our 15 pound turkey, we’ll say the final cook time is 11 hours at 225oF in the electric smoker.

Spatchcocked turkey

If Julia Child was the first queen of celebrity chefs, Martha Stewart eventually took her crown, and so we have to include a recipe of Martha’s.  Martha Stewart’s magazine featured a recipe for a spatchcocked turkey, a method of cooking poultry in which bones are removed so the bird can be flattened and cooked more evenly and quickly.
Martha Stewart’s recipe has the oven preheated to 450oF, with a 12 pound and fully spatchcocked turkey roasted for 1 hour 10 minutes. For our 15 pound turkey, we’ll adjust this to be cooked in the oven at 450oF for 85 minutes.

Sous vide turkey

Sous vide cooking, or the process of cooking food that is vacuum-sealed in a plastic pouch by placing it in heated and circulating water bath, has been around for decades. The method has gained traction more recently, however, as home cooks are increasingly getting their hands on the cooking equipment necessary that was previously only available in professional kitchens. The cooking method allows meat to be cooked at lower temperatures and thus cooked more evenly, safely, and while retaining moisture.

If you are in the market for a sous vide immersion circulator, one of the first places you might go is Williams Sonoma. To aid the new owners of this equipment, they also offer up a sous vide turkey recipe by Michael Voltaggio. The water of the sous video immersion circulator is preheated to 150oF and the vacuum sealed turkey pieces then placed in and cooked for 2 hours 30 minutes.

Calculations

These recipes use a wide variety of cooking apparatuses and fuels, so the methodology of calculating the total energy use and associated CO2 emissions will vary. Much like the Halloween-themed post on the most sustainable way to light your Jack-O’-Lantern, this post will thus be calculating very rough estimates using educated choices of data and assumptions. The final numbers should be considered back-of-envelope calculations and not scientifically or rigorously tested. There are also various aspects to the cooking process that would impact the end result that will not be accounted for, as well as variables to your individual cooking efforts that would change the final result (e.g., size of oven or grill, the energy mix of your power supplier, what type of propane or charcoal you buy from the store).

All that said, if you have ideas or suggestions on how to refine any of the numbers calculated here, then please reach out and/or leave a comment! (For one, I’ve assumed an oven is using a uniform amount of power regardless of the temperature at which it is set. While the difference of power use at 350oF and 450oF is not likely that much, it is definitely measurable. However, after much digging I was still unable to find any way to estimate the power difference among different temperatures, so a uniform power consumption was chosen and used for all use of the oven.)

Regardless of fuel type, all final energy numbers are calculated in kilowatt hours (kWh) and all CO2 emissions are calculated in lbs.

If you don’t care about going through the calculations and just want to jump to the final numbers, click here to jump to the results!



Roasted turkey

We are assuming the use of an oven for 3 hours 15 minutes. The oven will also need to preheat the oven, which we’ll assume to take 15 minutes. All together, the energy use and CO2 emissions will be associated with using an oven for a total of 3 hours 30 minutes.

In the United States, ovens are commonly powered by either electricity or by natural gas (though electric stoves are almost twice as common as gas stoves). The fuel type will affect the end energy use and CO2 emissions:
Electric oven:

Electric ovens use about 2.0 kilowatts (kW) of power. Assuming this power usage for the entirety of the recipe, the energy use of roasting the turkey in an electric oven is about 2.0 kW times 3.5 hours, or 7.0 kWh.

The latest data available from the Department of Energy says that for every kWh of electricity produced in the United States, 1.096 pounds of CO2 are released. Thus for this recipe in an electric oven, the CO2 emissions are equal to 1.096 lbs/kWh times 7.0 kWh or about 7.7 pounds of CO2.

Gas oven:

Gas ovens use about 0.112 therms of natural gas per hour. Over the course of the 3 hours 30 minutes, this would result in the use of 0.392 therms. In order to convert this amount of natural gas to kWh for comparison’s sake, we use the energy equivalence of one therm being about 29.3 kWh, meaning the energy use of a gas oven for this recipe is 11.5 kWh.

The Environmental Protection Agency (EPA) has a handy carbon footprint calculator you can use to analyze the CO2 emissions of all sorts of household activities. Included among its assumptions is the emission factor of cooking with natural gas, at 11.7 lbs of CO2 per therm of natural gas (this is another place where your specific situation may vary– some gas stoves use propane or other flammable gases as fuels, but we’ll assume natural gas for the sake of this calculation). Based on this assumption, the roasted turkey recipe in a gas oven would result in CO2 emissions of about 4.6 lbs of CO2.

Braised turkey

The braised turkey recipe also uses a oven, but this time for 15 minutes of preheating and 3 hours 30 minutes of cooking for a total of 3 hours 45 minutes. Again, this process can be done in an electric or a gas oven using the same assumptions as the roasted turkey.

Source

Electric oven:

Using the same assumptions as above for 3 hours 45 minutes of 2.0 kW power usage, the braised turkey recipe uses 7.5 kWh. Using the same assumption of 1.096 lbs of CO2 per kWh results in the CO2 emissions of the braised turkey in an electric oven being about 8.2 lbs.

Gas oven:

Repeating the assumptions above again gives an approximate energy use of 0.420 therms, or 12.3 kWh, and would result in emissions of about 4.9 lbs of CO2.

Deep fried turkey

The deep frying recipe calls for a propane heater to preheat a pot of oil to 250oF, adding in the turkey and raising the temperature to 350oF, and then cooking for 40 minutes.
 

The assumptions we can make here are that a propane cooker uses 65,000 British thermal units (BTUs) per hour and preheating deep fryers takes about 30 minutes. That means the total energy use would be 65,000 BTU/hour times 1 hour 10 minutes for a total of 75,833 BTU. Converting the propane use in BTU to approximate energy use in kWh gives a final result of approximately 22.2 kWh.

To calculate the CO2 emissions from this cooking process, the EPA’s carbon footprint calculator again gives us the needed information of CO2 emissions for cooking by propane. With the EPA assumption that every million BTU of propane burned emits 136.05 lbs of CO2, the deep fried turkey’s 75,833 BTU emits about 10.3 lbs of CO2.

Grilled turkey

Charcoal grill:

When the grilled turkey recipe for a charcoal grill is used, 110 charcoal briquettes are used over the course of 3 hours (after 30 minutes of pre-burn of charcoal).

Experiment shows that the energy content of charcoal is 7.33 kilojoules (kJ) per gram, while a single briquette of charcoal weighs about 25.7 grams. All together, this means a charcoal grilled turkey takes 20,733 kJ, which is converted to about 5.8 kWh.

For the CO2 emissions of charcoal grilling, Oak Ridge National Laboratory has found that the amount of charcoal needed to operate a grill for an hour emits 11 pounds of CO2. For this recipe that uses the grill for a total of 3 hours 30 minutes, that amounts to 38.5 pounds of CO2.
Propane grill:

When prepared on a gas grill, propane is needed to preheat for about 15 minutes and then cook the turkey for 3 hours.

The rate of propane use in propane grills varies, but a standard gas grill is rated at about 36,000 BTU/hour. That means for the full 3 hour 15 minute operation, the Butterball grilled turkey recipe requires 117,000 BTU or approximately 34.3 kWh of energy.
 
As with the recipe for deep fried turkey, we can use EPA’s assumption that every million BTU of propane burned emits 136.05 lbs of CO2, meaning this propane grilled turkey accounts for 15.9 lbs of CO2.

Smoked turkey

For the smoked turkey recipe, we again have two options for cooking fuel– either a charcoal fueled water smoker or an all electric smoker.

Charcoal powered water smoker:
This recipe required the burning of 10 pounds plus 70 briquettes of charcoal for 8 hours (after 15 minutes of preheating).
Using the same assumptions as with the charcoal grilled turkey, we find that at 7.33 kJ/gram of charcoal and 25.7 grams of charcoal per briquette gives a total energy use of the charcoal for a turkey smoked with a water smoker of about 12.9 kWh.
For the CO2 emitted, we again assume that grilling for an hour emits 11 pounds of CO2 per hour, meaning for a total grill time of 8 hours 15 minutes we get 90.8 lbs of CO2.
Electric smoker:
The electric smoker will be set at 225oF and the turkey cooked for 11 hours. Common electric smokers are rated at about 800 Watts, meaning 11 hours of use would use 8.8 kWh.
Since this is all electric, we can reuse our assumptions from cooking in an electric oven. Assuming 1.096 lbs of CO2 are released for every kWh of electricity produced in the United States, the electric smoker would account for about 9.6 lbs of CO2.

Spatchcocked turkey

The recipe for spatchcocked turkey brings us back to the oven, but with the distinct (and intentional) advantage of a greatly reduced cooking time compared with the other methods. The 15 pound turkey will cook in the oven at 450oF for 85 minutes, after 15 minutes of preheating, for a total oven use time of 1 hour 40 minutes.
Electric oven:
Reusing our electric oven assumptions, 1 hour and 40 minutes of 2.0 kW power usage means the spatchcocked turkey will require about 3.3 kWh of energy. At 1.096 lbs of CO2 per kWh, that means the recipe accounts for about 3.6 lbs of CO2.
Gas oven:
If instead the spatchcocked turkey is cooked in a gas oven, which uses 0.112 therms of gas per hour, the energy use of this recipe would be about 5.5 kWh, while the CO2 emissions associated with this cooking process would be 2.2 lbs.

Sous vide turkey

Last but not least is the sous vide turkey, which requires the use of an immersion sous vide immersion circulator for 2 hours 30 minutes (after a 15 minute preheat time). Given that the power rating of a sous vide from Williams Sonoma (the source of our recipe) is 1,100 W and the total operating time is 2 hours 45 minutes, the electricity use comes out to about 3.0 kWh. At 1.096 lbs of CO2 per kWh, that means the sous vide turkey accounts for about 3.3 lbs of CO2.

Graphical results and conclusions

With all those calculations and assumptions out of the way, we can finally look at all the results in one table:

Click to enlarge

These numbers can also be displayed graphically to show the overall level of ‘green-ness’ of each cooking method:

Click to enlarge

Looking at these results, there are a number of points of interest and interesting conclusions to draw:
  •  In terms of the amount of CO2 emissions, the two options that use charcoal (smoked in a charcoal smoker and grilled on a charcoal grill) are by far the greatest emitters. This result shouldn’t be surprising, as charcoal (with anthracite coal as one of its ingredients) is one of the more carbon intensive fuels you can use in your homes. However it is interesting to note that, despite their higher CO2 emissions, they are in the same ballpark in terms of energy use as the other cooking methods. This result shows how charcoal is an efficient fuel source, it just happens to also be dirty.
  • In terms of the total energy use, the two options that use propane (deep fried and grilled on propane grill) require the greatest energy. The higher energy needed is likely due to the cooking source being less efficient than others, with gas/propane burners typically being only 40% efficient with the remaining 60% of energy output being lost to heating the surrounding air or as visible light.
  • The two best cooking methods in terms of both minimal energy use and CO2 emissions are the sous vide turkey and the spatchcocked turkey (in either a gas or electric oven). The reason these reign supreme is telling, and different for the two of them.
    • For the sous vide turkey, the turkey is vacuum sealed and cooked in heated water the size of a typical pot. The result is that a smaller volume has to be heated up when compared with a larger oven, deep fryer, smoker, or grill that needs to heat up and keep heated the larger surrounding area. By focusing the heat in a smaller area, the total energy use is greatly reduced. In all cooking, the smaller the area you are heating up the more energy efficient the cooking process will be, which is why it is actually advisable to cook using smaller, dedicated appliances (e.g., toaster ovens, panini press, etc.) than to use the oven or stovetop for everything.
    • For the spatchcocked turkey, the reduced energy use and associated CO2 emissions is simply attributed to the largely reduced cooking time. Outside of the deep fried recipe, which uses the aforementioned inefficient propane, the spatchcocked recipe is the only one that takes under two hours of cooking. Obviously, the less time you have to have your appliances working, the less energy you’ll use. So while spatchcocking may have become popular due to the convenience of reduced cooking time, the relative efficiency is also among its virtues.
  • When comparing the recipes that use either the gas oven or the electric oven, the final figures show that the gas ovens use more energy but emit less CO2. What is important to note about the CO2 difference, however, is that the numbers are based on the average U.S. figure for CO2 emitted per kWh. This number can vary greatly depending on your power company and where you live. For example, if you live in Vermont then your power likely comes from a greater proportion of renewable energy than in other states, which would reduce the relative CO2 emissions of your electric oven. Of course the opposite is true if your power company uses more coal in its fuel mix than the national average.
  • One last point is that the relative energy use here does not correlate to the relative cost to the consumer for preparing the turkey. Certain fuel types are much cheaper than others, which is part of the reason they are popular to use in the first place. For example, just because grilling by propane uses almost six times the energy as grilling by charcoal, the relative prices of the fuels actually results in grilling by gas being less costly per hour for a consumer.

According to the National Turkey Federation, 46 million turkeys are roasted each Thanksgiving. Various outlets have attempted to estimate the actual energy use of those turkeys cooked in aggregate, with answers ranging from 48 million kWh to 792 million kWh (quite a wide range, showing just how uncertain the true number is). Using the numbers calculated here, if all 46 million turkeys were cooked sous vide then that would be 138 million kWh, whereas if they were all grilled on a propane grill then that would be over 1.5 billion kWh. Concerning CO2 emissions, the 46 million turkeys could account for 152 million lbs (sous vide) or over 4 billion lbs (grilled on charcoal grill)– for context, a passenger vehicle emits about 10,000 lbs of CO2 per year. That’s all to say, the small decisions everybody makes individually can add up to make a large difference in total energy use or CO2 emitted– even when talking turkey.

In the end, though, there isn’t too much reason for you to stress. There are plenty of methods you can use to cut down on energy use while cooking if you choose to do so(see some examples here and here, or you can even invest in a solar cooker that uses just the sun and reflectors to cook at temperatures up to 400oF!). But again, the overall energy use on Thanksgiving is lower than the average Thursday. It’s a time to relax and be grateful, not necessarily to measure out your exact briquettes to minimize energy spent. But you can come to the Thanksgiving table with some of these fun facts handy to impress your family, just be sure to praise the cooking of the chef first– he or she spent plenty of time making that dinner!

Have a happy Thanksgiving!

Sources and additional reading

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.