Friday, June 22, 2012

It Ain't Easy Being Green

An interesting bit of good news this week: the U.S. has cut its greenhouse gas output. While part of this is due to the lackluster economy, and part is due to a turn to greater efficiency and renewable power, much is due to greater use of natural gas. While this is an improvement, it still adds CO2 to the atmosphere. There's a reckoning that simply must be made, eventually ... but do not delude yourselves that it will be an easy one.

The reasons why we need to cut our reliance on fossil fuels are many. The brown haze that hangs over most of our cities is one. The foreign entanglements that result from guaranteeing our access to petroleum is another. Still another is that we really don't know where this particular road ends. We're running an open-ended experiment on the effects of elevated CO2 concentrations, and that's probably not a great idea.

But we still need to face the fact that reversing our reliance on fossil fuels will not be easy. Let's look at a summary of our energy use from 2009, courtesy of the Lawrence Livermore National Laboratory:

That's a pretty big, pretty dense picture. But there's a lot of useful data here. Let's take a detailed look at where our energy comes from: (Note: Quad = Quadrillion BTU)

Total Energy, Non-Carbon Sources: 12.21 Quads

Total Electrical Energy Input: 38.19 Quads

Total Non-Electrical Input, Carbon Sources: 138.57 Quads

The interesting thing to note here is that we already realize almost a third of our electrical power from non-carbon sources. But if we were to totally go green electrically, we'd have to treble that capacity just to match our current power generation capability. That's a whole lot of generators. But it actually gets worse than that. Much worse. You see, to totally get off of carbon, we'd have to go to an all-electric energy economy. Which means that, every watt of energy we use, no matter where or how, would have to be delivered to the consumer over the power lines. And that's a problem.

A lot of energy gets eaten up between the generator and the consumer. Joule heating is a harsh taskmaster, and there's just no way to get around that. When you push electrical power down a line, you heat it up, and you cannot recover that waste heat. Basically, for every watt that's useful for the consumer, we need to drum up 3.16 watts at the generator. Which means that if we electrify the segments of the energy economy that currently aren't electric, we have to generate 3.16 times that power to effect that replacement.

That comes to (138.57 x 3.16), or 437.88 Quads. This brings the total energy budget up to 476.07 Quads, or nearly twelve and a half times as much power as we generated in 2009. Or, in terms of our then-current non-carbon energy sources, thirty-nine times our 2009 capacity.

OK, that's the bad news. Now for the good news: there is a clear road out of this mess. Ingenuity got us into this fix, and ingenuity can get us back out.

For one thing, with every year we come to a clearer and more complete understanding of the phenomenon of superconductivity. Every few years, the highest critical temperature creeps a little higher. There are three obvious applications. First, electrical motors become much more efficient, allowing for possibly less power demand by the consumer. Second, electrical generators become much more efficient (since generators and motors are mechanically about the same thing), making power plants themselves more efficient. And third ... a superconducting power line makes Joule heating go away. Give us superconducting power lines, and at a stroke we triple our deliverable power capacity. That's huge. Not enough to close the gap by itself, but it's still such a tremendous efficiency multiplier that it's worth just about any amount of research funding to make it happen.

For another, we're getting closer by the year to some pretty awesome large-scale power options.

For years now, I've been keeping an eye on the Polywell project. They're currently in the middle of a long-term U.S. Navy project to develop a potential fusion reactor. We don't know exactly how well they're doing, since the Navy wants them to play their cards close. But they haven't been shut down. This is a pretty strong indication that they're onto something. It's taking longer than I originally expected, but this is looking like a pretty strong contender to provide a lot of clean, abundant power. Especially if the p-B11 reaction pans out. Any controllable fusion reaction would be good news, since hydrogen is something we're unlikely to run out of before the Sun burns out ... but reactions that don't spray out stray neutrons are even better.

There are also some other strong candidates. Dense plasma focus is one, as well as the paths being explored by the National Ignition Facility and the Z-Machine. One of these is bound to work. Maybe even more than one.

So although we're in a fairly sticky situation, energy-wise, I don't think despair is called for. A lot of extremely brilliant people are working very, very hard on these problems. As long as they've got the resources they need to pursue their work, there's good reason to be hopeful.

Remember, we thought our way into this. We can think our way out.

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