What Is Sustainability? And What Is it Not?

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Clouds (original name: Nuages - image by luc.viatour, CC 2.0 licensed)

In their special issue on Earth 3.0, Scientific American explores the concept of “sustainability” and the myths surrounding it as we face an uncertain future. In Top 10 Myths about Sustainability, they observe:

When a word becomes so popular you begin hearing it everywhere … it means one of two things. Either the word has devolved into a meaningless cliché, or it has real conceptual heft. “Green” (or, even worse, “going green”) falls squarely into the first category. But “sustainable,” which at first conjures up a similarly vague sense of environmental virtue, actually belongs in the second.

The article then goes on to cover a number of myths – many related to disinformation-type campaigns about the environment, global warming, and fossil fuels – like:

  • Myth 2: Sustainability is all about the environment.
  • Myth 4: It’s all about recycling.
  • Myth 6: Sustainability means lowering our standard of living, and
  • Myth 9: Sustainability is ultimately a population problem.

Definitely worth reading, if just for the review (for my well-educated readers) and to get a good, relatively unbiased view of some of the issues and realities of sustainability.

H/T to Texas Sustainability for the link.

Numbers and Facts About Energy

Chocolate Chip cookies have a lot of energy content (image from Wikipedia, licensed under CC Attribution Sharealike 2.5 license
Chocolate Chip cookies have a lot of energy content (image from Wikipedia, licensed under CC Attribution Sharealike 2.5 license

One of my pet peeves is news stories about energy that say something like “Flokistan just added 100 MWs in solar panels to its grid. This is enough to power 150 homes,” with no further numbers. I always want to know the context, like how many MWs does Flokistan use? How many homes are there in Flokistan? How does 100 MWs in solar panels compare in cost with putting in 100 MWs of coal-fired powerplants, and how long will it take to pay back?

The energy field is full of numbers – cars emit 19 tons of CO2 per year, solar panels cost $0.20/kWh, PG&E just contracted for 800 MWs of solar power in California. They are used freely, but seldom put into context. So I was very happy to discover an interesting online resource over the weekend: Richard Muller’s U.C. Berkeley class “Physics For Future Presidents.”

In one semester, my goal is to cover the physics that future world leaders need to know (and maybe present world leaders too.

Chapter one, Energy and Power (and the physics of explosions), of his textbook is online (at least temporarily) and it’s fascinating. Most interesting is the table near the beginning comparing the energy content per gram of various substances, including TNT, gasoline, hydrogen, various batteries, an asteroid traveling at 30 km/sec, and even chocolate chip cookies.

For example, a gram of gasoline has about 15 times as much energy content as a gram of TNT, and about half again as much energy content as a gram of ethanol. Hydrogen has almost three times the energy content of gasoline per gram, but even as a liquid, hydrogen is only about 1/10 as dense as gasoline, meaning that per volume, it has about 1/3 the energy content. Muller’s paper is full of useful rules of thumb, such as the following:

Remember this: Compared to gasoline, liquid hydrogen has

  • 3 x more energy per gram (or per lb)
  • 3 x less energy per gallon (or per liter)

He then goes on to discuss the relative merits of different forms of energy for powering cars, noting that gasoline is a particularly desirable fuel given its very high energy content and ease-of-use compared to, say hydrogen. Or batteries – which have 100x less energy density than gasoline. He also explains why having a big meteorite or asteroid hit Earth would be a bad thing.

If you’re interested in the numbers around energy, and how to compare them, I can definitely recommend a reading this chapter. The course is also available via podcast – see here for links, and covers not just energy, but terrorism, nukes, space, and global warming.

I’d be interested in hearing your comments about Muller’s information. If you have sources that you use for energy-related numbers, let me know about those too. I’m putting together a reference site for these sources, which I’ll link to on this blog as a static page when it’s ready.

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Is this solar energy analysis is too simplistic?

According to this analysis from Clean Edge, (which I saw originally in the San Jose Mercury News, Solar energy cost may rival other forms soon, study says – SiliconValley.com):

Solar energy will cost the same as power produced by coal, natural gas and nuclear plants in about a decade, a report released Tuesday suggests. By then, the price parity could propel solar adoption so that it accounts for 10 percent of U.S. electricity generation by 2025

If you listen to this kind of thinking, solar energy (which is defined as what, by the way?) is still far more expensive than other kinds. But solar energy, even today, has a finite payback time – if I put solar collectors on my roof, for example, eventually they will pay for themselves.

So that’s one way it’s wrong.

Secondly, the study assumes that conventional energy prices will go up by 3% per year. That could be a slight underestimate. Didn’t we just experience a three month period where gas prices nearly doubled? (That’s 100%, folks!).

I can’t make any argument about the assumption that solar energy prices will come down 18% per year. That’s a lot, by one metric, but we’ve certainly seen large and faster price drops in high tech in the past. Even the iPhone last month, which dropped in price by almost 50% in less than a year. Sure, that was partly through some magic AT&T financial pixie dust, but to the user, it’s a clear 50% price cut. There’s no reason similar magic pixie dust, whether from the government or from the utilities themselves, won’t contribute to market price declines.

The claim that solar currently accounts for less than 1/10th of a percent of the U.S. energy supply today is fine. But the assumption that it will still be less than 1 percent in 2015 (seven years from now) is curious. If we start at .1 percent, and double our solar usage every year, we end up at 128 times as much – 12.8% of today’s total. This is the amazing power of Ray Kurzweil’s “Law of Accelerating Returns.” Even if it takes two years for each doubling, we’re still up a factor of 32x in seven years. That means 3.2% today’s usage. Our total energy usage may also go up (although there are very good reasons to think it may not go up much and and will be starting a downward trajectory), but for a 32x increase in solar supply to translate to 1% of our total energy use, total energy use would have to double. Not too likely in the U.S., where population growth has stopped, and SUVs are starting their long decline.

Finally, there’s good reason to believe that solar energy will actually have a much larger share of U.S. energy usage, due to the power of “negawatts” (as explained brilliantly by Amory Lovins in this series of talks at Stanford in 2007), in which efficiency turns out to be the most cost effective way to power industry and create profits. Oh, and by the way, it significantly reduces our energy usage, by as much as a factor of five to seven!

The article combines a couple of types of fallacious thinking – that technological progress is linear, for example, rather than geometric, and that other factors, such as the desire to reduce greenhouse gases or realizing the benefits of negawatts throughout the economy, don’t have an additional accelerating effect on technology changes.