Q&A: Bill Gates

Energy

(Page 3 of 6)

Tuesday, August 24, 2010
By Jason Pontin

You've talked about the need for "energy miracles." But we've been waiting for such breakthroughs for decades. TerraPower is a traveling-wave reactor, a design that dates back to the 1950s. We've been working on energy miracles--and we've seen nothing. Wouldn't we be better off making the energy technologies we have more efficient?

Well, no, we haven't been working on those things. The nuclear industry was effectively shut down in the late '70s. And so evolutionary improvements on those so-called Gen 3 designs really didn't happen. And more radical designs that were measured according to their economics didn't happen. There's a lot of paper designs under the heading Gen 4, but most of those are going to be very, very expensive. They're kind of cool science, but they're very, very expensive.

But let me get back to the main thrust of your question. The CO₂ problem is simple. Any amount you emit causes warming, because there's about a 20 percent fraction that stays for over 10,000 years. That's the way the ocean equilibrates with the air on this planet. So the problem is to get essentially to zero CO₂ emissions. And that's a very hard problem, because you have sources like agriculture, rice, cows, that are single-point sources out with the poorest people. So you better get the big sources: you better get rich-world transport, rich-world electricity, and so on to get anywhere near your goal. And so when people say, "Shouldn't we do X or Y or Z?"--well, if X or Y or Z gets you a 20 percent reduction, then you've just got the planet, what, another three years? Congratulations! I mean, is that what we have in mind: to delay Armageddon for three years? Is that really it? A 20 percent reduction is interesting, and it's on the way to a 40, 60, 80 percent reduction, but most things that are low-hanging fruit are not scalable. The U.S. uses, per person, over twice as much energy as most other rich countries. (Put Canada and Australia aside, because they are almost as bad as us.) And so it's easy to say we should cut energy use by building better buildings and higher MPG and all sorts of things. But even in the most optimistic case, if the U.S. is cutting its energy intensity by a factor of two, to get to European or Japanese levels, the amount of increased energy needed by poor people during that time frame will mean that there's never going to be a year when the world uses less energy. In other words, there is absolutely no hope if you just say the world should use less energy. The only hope is less CO₂per unit of energy. It may feel good for people to use less energy, and they should--if individually they can delay Armageddon for about one microsecond, everybody should do that--but you ought to save the political will and the money to make sure you're doing the thing that really has a chance of solving the problem, and that's CO₂ intensity. And no, there is no existing technology that at anywhere near economic levels gives us electricity with zero CO₂.

Then what kinds of energy miracles do we need?

You know, take wind: it's actually not that far from economical when it makes up the last 20 percent of the energy supply. But almost everything called renewable is intermittent. I also have another term for it: "energy farming." The density is very low. We have no idea how to take those intermittent sources up to 50, 80, 90 percent. You can see this in microcosm in the Texas grid. When wind was like 2 percent, they would let the wind guys bid low and then fail to deliver, with no penalty. Well, now wind is up to about 8 percent of the Texas grid. And so the guys who are maintaining the standby power, which is mostly natural gas, are saying, "Hey, when the wind guys fail, shouldn't they pay at least a penalty? Because most times they don't fail, and yet we've always had to maintain this backup for them." It just points up that without a storage miracle, you cannot take intermittent sources up to large numbers. In fact, not only do you need a storage miracle, you need a transmission miracle, because the intermittent sources are not available in an efficient form in all locations.

Now, energy factories, which are hydrocarbon and nuclear energy--those things are nice. Well, they have some nice things and some not-nice things. You can put a roof on them if you get bad weather: most coal plants have been built to withstand the 20-year hurricane. But energy farming? Good luck to you! Hail, wind, dust--what is your lifetime? Energy factories can be anywhere. They can withstand tough conditions. Unfortunately, conventional energy factories emit CO_2, and that is a very tough problem to solve, and there's a huge disincentive to do research on it. People are willing, but until society decides that the government's willing to certify storage locations and take the long-term risk and do the monitoring of trillions of cubic feet of CO₂, it can't happen. The complexity of managing, say, 50 years of U.S. carbon emissions--it makes Yucca Mountain look like the most trivial exercise ever contemplated. I happen to think that if you have the political will, the technical problems could be solved.

Let's talk about policy, then. The prospects for a strong climate bill in the U.S. Congress now look dim. And so do the chances for any binding international treaty. But almost everyone agrees that there needs to be a price on carbon--whether a Pigovian tax [a kind of tax levied on a market activity that generates negative externalities, named after the British economist Arthur Pigou] or a cap-and-trade system. Without a price, there's going be very little incentive to do the kinds of research, or create the kinds of technologies, or build out the kind of infrastructure, that we need.

No, that's not right. It's ideal to have a carbon tax, not just a price on carbon, which is this fuzzy term that includes cap-and-trade.