Reader’s Forum, Take 1

Posted on 2011-12-22 by tmurphy

I try to run a tight ship on comments, keeping discussion focused on the post topic, and in accordance with the discussion policy. But I sympathize with those who want to go off-road, since the overall topic is vast and has many threads—and I have not discussed some major components of the story yet. So as a holiday gift to Do the Math readers, I open here a discussion forum open to all topics involving growth, energy, fossil fuels, renewables, nuclear, demand and behaviors, societal hurdles, political facets, visions of the future, etc. This is your chance to express the big-picture points that may not fit within the narrow confines of ordinary on-topic discussions.

I will reject only comments that I deem to be uncivil, too far from Do the Math concerns, or so lengthy that I don’t have time to screen them (and long screeds also discourage readers and are therefore less likely to be read). If you’re tempted to write a long essay, I highly recommend starting a blog of your own (it’s not really that hard). Then you can summarize a thesis in a few sentences and point to the larger content elsewhere. So there you have it—now go nuts!

How Much Dam Energy Can We Get?

Posted on 2011-12-20 by tmurphy

[An updated treatment of some of this material appears in Chapter 11 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

Having now sorted solar, wind, and tidal power into three “boxes,” let’s keep going and investigate another source of non-fossil energy and put it in a box. Today we’ll look at hydroelectricity. As one of the earliest renewable energy resources to be exploited, hydroelectricity is the low-hanging fruit of the renewable world. It’s steady, self-storing, highly efficient, cost-effective, low-carbon, low-tech, and offers a serious boon to water skiers. I’m sold! Let’s have more of that! How much might we expect to get from hydro, and how important will its role be compared to other renewable resources?

Last week, as soon as I put tidal power into a box labeled “waste of time,” I received some deserved howls of protest. I saw it coming, and had built in words to soften the “waste of time” label. But it was a poor choice from the start. A better set of labels is “abundant,” “potent,” and “niche.” The last could also be thought of as “boutique,” in that it is cute, perhaps decorative, may serve some function, but will never be a heavy lifter. The “potent” label—formerly “useful”— is meant to indicate a source that could supply a healthy fraction (say over a quarter) of our global demand if fully exploited. We will never fully exploit any resource, so the numbers at least need to support ¼-scale before we can believe that it may play a major role.

I should also point out that all along, my approach is to pretend that our goal is to keep up our current energy standards in a post-fossil-fuel world. In the process, we will see just how hard that will be to do. It is by no means impossible, but it’s much more difficult and compromised than most people realize. In the end, it is not clear that we will maintain our current global rate of energy usage: the future is unwritten. On the plus side, some of the approaches I cast into the “niche” box may become “potent” in a scaled-down world. Firewood was once abundant, then moved to potent, and is now a niche. But a reversal of fortunes could change all that.

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Can Tides Turn the Tide?

Posted on 2011-12-13 by tmurphy

[An updated treatment of some of this material appears in Chapter 16 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

Now is the time on Do the Math when we scan the energy landscape for viable alternatives to fossil fuels. In this post, we’ll look at tidal power, which is virtually inexhaustible on relevant timescales, is less intermittent than solar/wind (although still variable), and uses old-hat technology to make electricity. For this exercise, we mainly care about the scale at which the alternatives can contribute, leaving practical and economic considerations sitting in the cold for a bit (spoiler alert: most are hard and expensive). Last week, we looked at solar and wind, finding that solar can satisfy our current demand without batting an eyelash, and that wind can be a serious contributor, although apparently incapable of carrying the load on its own. Thus we put solar in the “abundant” box and wind in the “useful” box. There’s an empty box labeled “waste of time.” Any guesses where I’m going to put tidal power? Don’t get upset yet.

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Wind Fights Solar; Triangle Wins

Posted on 2011-12-06 by tmurphy

[An updated treatment of some of this material appears in Chapters 12 and 13 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

For me, the most delightful turn of events in the ultimate nerd-song “Particle Man” by They Might Be Giants, is that after introducing (in order of complexity) particle-man, triangle-man, universe-man, and person-man—and learning that triangle-man naturally beats particle-man in a match up—we pit person-man against triangle-man to discover that triangle wins—again. In this post, we’ll pit solar against wind and see who wins.

I will take my usual approach and estimate what I can—as opposed to researching the results of detailed studies. It’s part of the process of personal mastery of the big-picture issues, while also providing a sanity-check. In exploring useful reactions to the looming peak oil crisis (or pick your favorite rationale for weaning ourselves from fossil fuels), an appropriate strategy is to assess ballpark capacities of the various options. Some will prove to be orders-of-magnitude more prodigious than we need, others will be marginal, and many will show themselves to be woefully inadequate to match the required scale. So the goal is to perform this crude sorting process into abundant, useful, and waste of time.

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MPG of a Human

Posted on 2011-11-29 by tmurphy

On Do the Math, three previous posts have focused on transportation efficiency of gasoline cars, electric cars, and on the practicalities of solar-powered cars. What about personal-powered transport—namely, walking and biking? After stuffing myself over Thanksgiving, I am curious to know how potent human fuel can be. How many miles per gallon do we get as our own engines of transportation?

Okay, the “miles” part is straightforward. And we can handle the “per.” But what’s up with the gallon? A gallon of what? Here we have all kinds of options, as humans are flex-fuel machines. But food energy is not much different from fossil fuel energy in terms of energy density.

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A Solar-Powered Car?

Posted on 2011-11-22 by tmurphy

If you like the sun, and you like cars, then I’m guessing you’d love to have a solar-powered car, right? This trick works well for chocolate and peanut butter, but not so well for garlic bread and strawberries. So how compatible are cars with solar energy? Do we relish the combination or spit it out? Let’s throw the two together, mix with math, and see what happens.

What Are Our Options?

Short of some solar-to-liquid-fuel breakthrough—which I dearly hope can be realized, and described near the end of a recent post—we’re talking electric cars here. This is great, since electric drive trains can be marvelously efficient (ballpark 85–90%), and immediately permit the clever scheme of regenerative braking.

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Pump Up the Storage

Posted on 2011-11-15 by tmurphy

If we adopt solar and wind as major components of our energy infrastructure as we are weaned from fossil fuels, we have to solve the energy storage problem in a big way. An earlier post demonstrated that we do not likely possess enough materials in the world to simply build giant lead-acid (or nickel-based or lithium-based) batteries to do the job. Comments frequently pointed to pumped hydro storage as a far more sensible answer. Indeed, pumped storage is currently the dominant—and nearly only—grid-scale storage solution out there. Here, we will take a peek at pumped hydro and evaluate what it can do for us.

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The Biofuel Grind

Posted on 2011-11-08 by tmurphy

[An updated treatment of some of this material appears in Chapter 14 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

When we enter the decline phase of conventional oil—likely before 2020—we will scramble to fill the gap with alternative liquid fuels. The Hirsch Report of 2005, commissioned by the U.S. Department of Energy, took a hard look at alternatives that could respond to the scale of the problem in time to have an impact. Not one of the approaches deemed to be currently viable in the report departs from fossil fuels. But what about biofuels? To what extent can they solve our problem? We’ll dip our toes into the math and see where a first-cut analysis leaves us.

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Growth Has an Expiration Date

Posted on 2011-11-05 by tmurphy

Just a quickie. A few weeks back, I tried to cram four Do the Math posts into a 20 minute talk, delivered at the Compass Summit. For those of you who would rather watch 23 minutes of video than sit down to read four posts, here is a link to the video of the talk. Perhaps you’ll see why I should stick to writing.

Growth Has an Expiration Date from Compass Summit on FORA.tv

Peak Oil Perspective

Posted on 2011-11-01 by tmurphy

It was by teaching a course on energy in 2004 that I first became aware of the enormous challenges facing our society this century. In preparing for the course, I was initially convinced that I would identify a sensible and obvious path forward involving energy from solar, wind, nuclear, geothermal, tides, waves, ocean currents, etc. Instead, I came out dismayed by the hardships or inadequacies on all fronts. The prospect of a global peak in oil production placed a timescale on the problem that was uncomfortably short. It took several exposures to peak oil for me to grasp the full potential of the phenomenon to transform our civilization, but eventually I was swayed by physical and quantitative arguments that I could not blithely wave off the problem—despite a somewhat unsettling fringe flavor to the story.

Aside from excursions here and there, Do the Math represents—in computer terms—a “core dump” of years of accumulated thoughts and analysis on energy, growth, and the largely unappreciated challenges we face on both short and long terms. During this queued process—with much more to come—I have made references to peak oil, but have refrained from a head-on treatment. As important as peak oil has been in motivating my quantitative exploration of life beyond fossil fuels, it seems overdue that I share my thoughts.
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