Do the Math Turns One: Place Your Orders

One year ago today, Do the Math was born with a post on the absurdity of continued growth—in this case illustrating a Galaxy-consuming civilization in a mere 2500 years. Within a month, the site was getting thousands of pageviews per day, as I cranked out a backlog of thoughts and analysis surrounding the energy challenges we face.

In the process, adhering to a weekly schedule forced me to perform many new calculations on topics I had not previously explored very deeply. So besides being a cathartic experience, I gained new understanding, finding the exercise of constructing the alternative energy matrix to be particularly clarifying. One of the major lessons for me has been that while the physical scale of any alternative energy resource is important—and sometimes a showstopper—more often it’s the practical limitations that form the biggest barriers.

Finding the time and (mental) energy to keep the blog rolling has been challenging, but it’s you folks who inspired me to keep trucking. Knowing that each post would be read by thousands, and knowing that I could look forward to some excellent and thought-provoking (although sometimes just provoking) comments made the enterprise worthwhile.

At this point, I have dropped the cadence to bi-weekly, and my list of future topic ideas is slowly being whittled down. Many comments in the past have requested that I write a post about issue or another. I invite you to submit requests (even if repeated) in the comment forum below. Note that I might not have the background, interest, or time to invest if serious analysis is required. But there is some chance I’ll take the bait—and the idea may already even be on my list! Please refer to the Guide to Posts for a refresher of what’s been covered already.

Also, I think it fitting on this first anniversary to extend a note of gratitude to Asher Miller of the Post Carbon Institute for inspiring me to start writing, and for putting me in touch with the fine folks at the Energy Bulletin. The EB editors: Bart Anderson, Kristin Sponsler, and Simone Osborn offered early guidance and good advice (plus instant readership) that was vital to getting Do the Math off the ground. So a hearty thanks to these folks! 1.5 million pageviews later, their contributions have clearly had an impact.

And thanks to you, the readers, for your role in making this a successful and rewarding endeavor.


My wife calls it spying. I call it data. To-may-to, To-mah-to. It’s true that I know what she’s been up to (electrically) while I’m away. And it’s true that I can access this information anywhere in the world that has an internet connection. But domestic surveillance is not my aim (cameras and microphones would be far more informative in that regard). I just care about the energy angle.

In this post, I will present example results from monitoring and recording my home electricity use, demonstrating the marvelous secret world it reveals. My interest lies in putting numbers on my own behaviors, and in characterizing the appliances in my house. Some of this rubs off on my wife, and some of it rubs her the wrong way. But as I explained in an earlier post, I kept a note she once wrote that said: “Okay, TED’s pretty cool.”

Who is TED? TED is The Energy Detective. That same earlier post told the story of TED’s tortured journey to our home—a tale of excitement, rejection, and ultimate acceptance.

This post is not meant to convey anything deep and meaningful about the energy challenges we face, except for the fact that those challenges provided a background motivation for me to explore and monitor energy data in my home (it should be obvious by now that I’m a data-holic). Rather, I will simply showcase a number of data captures from TED so you can see for yourself the interesting hidden behaviors of appliances, and develop some intuition about how much of a toll various devices take.

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Ruthless Extrapolation

We humans owe much of our success to our ability to recognize patterns and extrapolate trends to anticipate a future state. My cats, on the other hand, will watch a tossed toy mouse travel toward them across the room—getting ever-bigger—all the way until it smacks them between the eyes (no, they’re not strapped down—I’m not that sort of scientist). But far beyond an ability to avoid projectiles, our ancestors were able to perceive and react to changes in local food and water supplies, herd movements, seasonal cues, etc. Yet this fine tool can be over-used, and I see a lot of what I call ruthless extrapolation. In almost every case, extrapolation works until it doesn’t.  When the fundamental rules of the game change, watch out!

As with many aspects of human behavior, some of the finest commentary on the matter is served up by The Simpsons. In one episode, Lisa Simpson is taken to the orthodontist to evaluate whether or not she needs braces. The “doctor” runs a simulation based on current growth rates, producing an alarming graphic of teeth gone wild.

Image obtained from

Marge shrieks and is ready to do whatever it takes to protect her daughter against this cruel fate. Extrapolation can, of course, be used to argue both for impending doom or future prosperity—sometimes based on the same data. I started this blog with an extrapolative foil to demonstrate the insanity of continued physical growth, in fact. A tangential follow-up illustrated the hopelessness of differentiating a steady-state energy future from an energy crash using current data (although a continued exponential rise is already a poor fit).

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Heat Pumps Work Miracles

Part of the argument that we cannot expect growth to continue indefinitely is that efficiency gains are capped. Many of our energy applications are within a factor of two of theoretical efficiency limits, so we can’t squeeze too much more out of this orange. After all, nothing can be more than 100% efficient, can it? Well, it turns out there is one domain in which we can gleefully break these bonds and achieve far better than 100% efficiency: heat pumps (includes refrigerators). Even though it sounds like magic, we still must operate within physical limits, naturally. In this post, I explain how this is possible, and develop the thermodynamic limit to heat engines and heat pumps. It’s a story of entropy.

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Burning Desire for Efficiency

Ever wonder how efficient it is to heat water? Of course you have! Ever measured it? Whoa, mister, now you’ve gone too far!

I recently devised a laser-phototransistor gauge to monitor my natural gas meter dial—like ya do. As a side benefit, I acquired good data on how much energy goes into various domestic uses of natural gas. Using this, I was able to figure out how much energy it takes to heat water on the stove, cook something in the oven, or heat water for a shower. Together with the knowledge of the heat capacity of water, I can compute heating efficiency from my measurements. What could be more fun? I’ll share the results here, some of which surprised me.

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Chris Martenson Podcast

I’ll cheat on my bi-weekly posting plan and slip in this podcast conversation between Chris Martenson and myself, covering many of the topics I have written about in the last year.

If you don’t have 45 minutes, and are a faster reader than I am, a transcript is also available—mercifully leaving out many utterances of “um” and “you know” (which is all I seem to hear when I listen to a recording of myself).  The original source and surrounding intro/write-up can be found on the Chris Martenson website.

Spectral Extravaganza: The Ultimate Light

What do you get when you cross an astronomically-inclined physicist with concerns over energy efficiency in lighting? Spectra. Lots and lots of spectra. In this post, we’ll become familiar with spectral characterization of light, see example spectra of a number of household light sources, and I’ll even throw in some mind-blowing photos. In the process, we’ll evaluate just how efficient lighting could possibly be, along the way understanding something about the physiology of light perception and the definition of the increasingly ubiquitous lighting measure called the lumen. Buckle your physics seat-belt and prepare to think like a photon.

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Supermoon Disappointment

Putting on my astronomer hat, as one whose main research focus involves measuring the distance between the Earth and Moon, I feel compelled to “speak out” about the “supermoon” hype that crops up periodically.

Last night’s full moon was touted to be a “supermoon”—larger than normal.  As a result, many folks made it a point to watch the Moon rise.  I love the fact that people are paying attention to the Moon, getting outside, and enjoying the serene experience of watching the Moon creep over the horizon.  What I don’t like is that the hype leads to an overall sense of disappointment in many.  Is the campaign a net positive, or a net negative?  I don’t know.

In this post, we’ll look at the numbers and see just how special the supermoon is.

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My Neighbors Use Too Much Energy


I have described in a series of posts the efforts my wife and I have made to reduce our energy footprint on a number of fronts. The motivation stems from our perception that the path we are on is not sustainable. Our response has been to pluck the low-hanging fruit, demonstrating to ourselves that we can live a “normal” life using far less energy than we once did. We are by no means gold medalists in this effort, but our savings have nonetheless been substantial. Now we shift the burden off of ourselves, and onto our neighbors. You don’t have to run faster than the bear—just faster than the other guy. In this post, I summarize our savings relative to the national average, add a few more tidbits not previously covered, put the savings in context, and muse about ways to extend the reach of such efforts.

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Flex-Fuel Humans

If you’re one of those humans who actually eats food, like I am, then a non-negligible part of your energy allocation goes into food production. As an approximate rule-of-thumb, each kilocalorie ingested by Americans consumes 10 kilocalories of fossil fuel energy to plant, fertilize, harvest, transport, and prepare. The energy investment can easily exceed a person’s household energy usage—as is the case for me. But much like household energy, we control what we stick in our mouths, and can make energy-conscious choices that result in substantial reductions of energy consumption. I now call myself a flexitarian, a term acknowledging that my body is a flex-fuel vehicle, but also that I need not be rigid about my food choices in order to still make a substantial impact on the energy front.

An earlier post on how many miles per gallon a human gets while walking or biking touched on the fact that fossil fuels undergird our food supply. As a result, walking to the grocery store effectively uses as much fossil fuel as would a typical sedan. The lesson is not to walk less, but to change that 10:1 ratio for the better by eating more smartly. Once upon a time, we put less than one kilocalorie of energy into food production per kilocalorie obtained (or else we and our draft animals would have starved to death). So the 10:1 ratio is not at all inescapable, and depends strongly on the foods we choose to eat.

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