Friday, May 03, 2013

End of Carbon: A Herculean Effort

Every once in a while, I revisit the topic of the end of fossil fuels. The basic point hasn't changed much: while we need to get off of fossil fuels, we have to face up to the fact that if we do, we face an enormous energy shortfall. That is, unless we've taken the steps needed to get ready. Ordinarily I have an aversion to repeating myself. But in this case I make an exception. For one, it's a very important point, one that's glossed over far too often. For another, I like to look at the most recent data available.

And when I went to look for the most recent data available, I made an important discovery. There's actually a government office whose job it is to keep track of this stuff. Who knew? The U.S. Energy Information Administration, among other things, keeps a summary of American energy production and usage here. The data for 2011 is shown below:

Wow, that's much easier to read than the others I've seen.

First, there are some general points to make. When we're talking about oil, we're mostly talking about transportation. By a large margin (71%), our oil usage involves moving people and things from Point A to Point B. Natural gas is a utility player, about a third each going to electricity, homes, and industry. And coal is predominantly (92%) used for generation of electricity. If we want to get off of fossil fuels entirely, we need to replace that watt-for-watt with something else, most likely in the form of electricity, generated at a power plant and then delivered to the customer.

As I've said before, the biggest problem here is that you lose an enormous amount of energy in transmission. The rule of thumb is that you have to generate three watts of power at the plant to realize one watt at the wall outlet. There aren't many good ways to get around Joule heating.

So: in 2011 we generated a total of 97.2 quadrillion BTUs. Of that, 79.8 quads came from carbon-based sources. If we had to replace 79.8 quads at three-for-one, we'd need to generate a grand total of 256.8 quadrillion BTUs of power. Which means, we'd be generating about three times as much power as we do today. Or more to the point, we'd have to generate 15 times as much non-carbon power as we did in 2011.

It's actually not quite as bad as all that. There are two things that can work in our favor. First, some kinds of clean power we can locate at the point of use: solar panels, for example. In those cases, we can eliminate the transmission penalty. That won't cover every possible case, but it'll make enough of a difference to move the needle a little. Let's assume it's possible 25% of the time. In that case, we'd need to generate 216.9 quads, bringing our extra power required down to a multiple of 12.5 from 15.

The other possibility is more speculative, but could have far-reaching possibilities. I've mentioned superconducting power lines before. It'll be a long time before they're possible, if they're ever possible, but they're worth looking into. The reason should be obvious. Joule heating scales with the product of the resistance and the square of the current. If the resistance is zero, the Joule heating is also zero.

That's huge. This way, the 39.3 quads of electrical power generated actually is 39.3 quads, rather than the 13.1 that's actually delivered, knocking 26.2 quads off of the deliverable power we need to generate.

That means we'd only have to come up with 53.6 quads of non-carbon power, or about 3/4 of what we'd have to come up with otherwise. That's a much, much easier prospect. Superconductor technology is worth every last penny that we can spend on it.

The question then becomes, with what can we replace oil, coal, and natural gas? That hasn't changed since the last time(s) I've written about this, but I'll recap anyway.

1) Solar power. Every environmentalist's go-to favorite, but not necessarily your go-to source for steady, reliable, day-to-day base load. It's a good answer for homeowners, especially homeowners in the South and Southwest, who get plenty of sunny days. There's poetic justice in using the Sun's rays to power the air conditioners that fight back against the Sun's heat. But, I really don't see photoelectric power running steel furnaces. It's a matter of scale.

2) Wind power. The second favorite of environmentalists everywhere. There's a lot of power to be extracted from wind, and if you've got it you may as well use it. There's a potential problem to be aware of, though; if you extract too much energy from the wind, you'll alter the climate without intending to. And we don't know yet how much is too much.

3) Tidal, geothermal, hydroelectric power. While useful, these are very dependent upon local conditions. Such as, having a coastline, or a big river, or local hot spot. But if you've got it you may as well use it. Waste not, want not.

4) Nuclear power. As much as environmentalists everywhere hate this particular N-word, there's no way around it: if we're truly serious about getting off of carbon, we have to make more use of atomic power. For all its problems, it provides large amounts of reliable base-load power. And when you look at the statistics on deaths per terawatt-hour, summarized here, nuclear power isn't nearly as dangerous as its foes claim. There are problems that must be dealt with, but those are problems of engineering, not of science. We could do this now, if we had the will. We could be off carbon in a decade. The question is, do you really want it?

5) Fusion power. It's the eternal dream -- the vast amounts of power of fission, but without the noisome radioactive waste. The problem is, we're not entirely sure how to do this yet. The interim results from the WB-8 unit are encouraging, to the extent that we've heard about them. The work is proceeding slower than hoped, but it's still proceeding. And Polywell was never the only game in town. Sooner or later, someone's cracking that nut, and with it, they crack the energy problem essentially forever. Just about everything you can see in the night sky is hydrogen. The most abundant element in the entire Universe is something we're very unlikely to run short of.

As I've said before, it's important not to delude ourselves: this is a huge task. But not an insurmountable one.  If we get started soon enough, we'll have the tools we need, when we need them.

But we don't have forever. It's about time we got started.

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