Category Archives: Energy

General treatment of the physics of energy

Do the Math Turns One: Place Your Orders

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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.

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Heat Pumps Work Miracles

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[An updated treatment of some of this material appears in Chapter 6 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

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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Spectral Extravaganza: The Ultimate Light

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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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My Neighbors Use Too Much Energy

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[An updated treatment of some of this material appears in Chapter 20 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

From www.christmasvacationcollectibles.com

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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Easing Off the Gas

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The Do the Math blog series has built the case that physical growth cannot continue indefinitely; that fossil fuel availability will commence a decline this century—starting with petroleum; that alternative energy schemes constitute imperfect substitutes for fossil fuels; and has concluded that a very smart strategy for us to adopt is to slow down while we sort out the biggest transition humans have ever faced. The idea is to relieve pressure on the system, avoid the Energy Trap, and give ourselves the best possible chance for a successful transformation to a stable future. Since building this case, I have described substantial adaptations in our home energy use, but have not yet addressed the one that bears most directly on the immediate problem: transportation and liquid fuels. Let’s take a look at what can be done here.

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OilPrice Interview

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If you’re interested, oilprice.com posted an interview polling my take on energy alternatives and related issues.  Regular Do the Math readers have likely heard much of it before, but perhaps will enjoy a different packaging…

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Space-Based Solar Power

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A solar panel reaps only a small portion of its potential due to night, weather, and seasons, simultaneously introducing intermittency so that massive storage is required to make solar power work at a large scale. A perennial proposition for surmounting these impediments is that we launch solar collectors into space—where the sun always shines, clouds are impossible, and the tilt of the Earth’s axis is irrelevant. On Earth, a flat panel inclined toward the south averages about 5 full-sun-equivalent hours per day for typical locations, which is about a factor of five worse than what could be expected in space. More importantly, the constancy of solar flux in space reduces the need for storage—especially over seasonal timescales. I love solar power. And I am connected to the space enterprise. Surely putting the two together really floats my boat, no? No.

I’ll take a break from writing about behavioral adaptations and get back to Do the Math roots with an evaluation of solar power from space and the giant hurdles such a scheme would face. On balance, I don’t expect to see this technology escape the realm of fantasy and find a place in our world. The expense and difficulty are incommensurate with the gains.

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The Way is Shut

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When I first approached the topic of societal energy in 2004, I became aware for the first time that our energy future was not in the bag, and proceeded to explore alternative after alternative to judge the viability and potential pitfalls of various options. I have retraced my steps in Do the Math posts, exposing the scales at which different energy sources might contribute, and the practical complexities involved. My spooky campfire version of the story, a la Tolkien: The Way is Shut.

Alright, I’m overstating things a bit. The good news is that there do exist energy flows and sources that qualify as abundant or at least potent. However, many of the alternatives represent ways to produce electricity, which applies only to about one-third of our current energy demand. The immediate threat is therefore the short term liquid fuels crunch we will see when the global petroleum decline commences within the decade.

In this post, I will reflect on the lessons we learn after having characterized the various alternatives to fossil fuels. There will still be some tidying-up to do on energy alternatives not treated thus far, but by and large the nature of content on Do the Math is about to pivot toward addressing the question “What can we do now?” In some sense, a common thread so far has been: “easier said than done,” or “don’t count on that technology saving our bacon.” I’ve closed all the exits to get your attention. We’re boxed in. Okay, the exits aren’t really closed: they’re just not as wide open as they would need to be for me to be complacent. So now we’ll start looking at ways to nose out of our box in a safe and satisfying way.

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Fossil Fuels: I’m Not Dead Yet

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From Monty Python: “Bring out your dead”

Having looked at the major alternatives to fossil fuel energy production (summarized here), we come away with the general sentiment that the easy days of cheap energy are not evidently carried forward into a future without fossil fuels.  That’s right, fossil fuels will be dead and gone.  Is it time to pile them on the cart to be hauled away?

In the slapdash scoring scheme I employed in the alternative energy matrix, the best performers racked up 5 points, whereas by the same criteria, our traditional fossil fuels typically achieved the near-perfect score of 8/10. The only consistent failing is in the abundance measure, which is ultimately what brings us all together here at Do the Math. Fossil fuels are presently used in abundance—85% of current energy use—but this is a short-term prospect, ending within the century. The first effects of decline may be close at hand.  Do I hear talk of nursing homes?

The gulf between fossil fuels and their alternatives tends to be rather large in terms of utility, energy density, practicality, ease of use, versatility, energy return on energy invested, etc. In other words, we do not merrily step off the fossil fuel ride onto the next one by “just” allowing the transition to happen. The alternatives come at a cost, and we will miss the golden days of fossil fuels. But wait…what’s that murmur?  Not dead yet?

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The Alternative Energy Matrix

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[An updated treatment of this material appears in Chapter 17 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

Breathe, Neo. I’ve been running a marathon lately to cover all the major players that may provide viable alternatives to fossil fuels this century. Even though I have not exhausted all possibilities, or covered each topic exhaustively, I am exhausted. So in this post, I will provide a recap of all the schemes discussed thus far, in matrix form. Then Do the Math will shift its focus to more of the “what next” part of the message.

The primary “mission” of late has been to sort possible future energy resources into boxes labeled “abundant,” “potent” (able to support something like a quarter of our present demand if fully developed), and “niche,” which is a polite way to say puny. In the process, I have clarified in my mind that a significant contributor to my concerns about future energy scarcity is not the simple quantitative scorecard. After all, if it were that easy, we’d be rocking along with a collective consensus about our path forward. Some comments have  asked: “If we forget about trying to meet our total demand with one source, could we meet our demand if we add them all up?” Absolutely. In fact, the abundant sources technically need no other complement. So on the abundance score alone, we’re done at solar, for instance. But it’s not that simple, unfortunately. While the quantitative abundance of a resource is key, many other practical concerns enter the fray when trying to anticipate long-term prospects and challenges—usually making up the bulk of the words in prior posts.

For example, it does not much matter that Titan has enormous pools of methane unprotected by any army (that we know of!). The gigantic scale of this resource makes our Earthly fossil fuel allocation a mere speck. But so what? Practical considerations mean we will never grab this energy store. Likewise, some of our terrestrial sources of energy are super-abundant, but just a pain in the butt to access or put to practical use.

In this post, we will summarize the ins and outs of the various prospects. Interpretation will come later. For now, let’s just wrap it all up together.

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