May 23, 2006 4:00 AM PDT
Newsmaker: Superweeds, air caves and the future of energySee all Newsmakers
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What about genetic modification?
Chu: We have to be careful. These plants that we make for energy are essentially going to be superweeds, if you think about it. They're going to grow very fast. But you can also make them sterile, and you can make them fragile in different ways. One of the things that plants have invented over the last several hundred million years is a molecule, lignin, that actually protects the cellulose from bacteria or fungus. That was nature's way, the plant's way, of allowing plants to thrive better. Fungi and microbes were out there to eat them up.
So by eliminating the link we can...
Chu: Yeah. That's why trees last so long: There is lots of lignin in there and they're harder to break down. It's actually amazing because when plants "invented" this stabilizing molecule, rotting (became) so slow that some of the tree fossilized, and that's how our coal started.
How about synthetic biology, where you take a genetic component of one cell and marry it with another to get a result?
Chu: Yes. It's a complicated thing. It's not as obvious: "Oh! This plant makes this; this thing makes that; and this organism makes this," and you put them together. The first thing that happens is you've got some dead organism. You've got a bunch of interlocking systems that have to work together. A lot of fundamental science has to be done along the way, which is one of the reasons why a lot of our best comprised fundamental scientists are getting excited about this.
Chu: We don't understand really fully a lot of the complex mechanisms that control the metabolism and control life in itself. You can try grafting-in nitrogen fixation, which people are beginning to do, or drought resistance or pest resistance. You would want to do this stuff even if you're not raising energy. Fertilizer comes from methane, which is natural gas. It's also a source of water pollution, because the modern agricultural methods are very heavily fertilizer-intensive and nitrate run-offs are polluting the water. It's a huge problem in California.
Eventually we'd like to actually make artificial stuff, capture sunlight and make chemical fuel. Why? Because, well, there's always this specter that we could unleash the Frankenstein weed.
If it's in a lab, it's easier to contain. Chu: I don't personally think that's the real issue. I think we can make them dependent on us so that if they ever get unleashed they die. We're actually encouraging these plants to do something that, if left in the wild, they would evolve away from that because it's not in their best survival interests. It is not a survival plan to grow much more corn kernels than they really need to reproduce. What we're going to do is, we're going to try to get them to suck in sunlight the way Americans suck in food.
One issue you don't hear as much about is hydrogen. Do a lot of people still believe hydrogen could be an alternate fuel of the future? Or are the production and storage issues much thornier than they first appeared?
Chu: Some reality has checked in. Hydrogen is actually an easier chemical fuel to make. But you never want hydrogen to generate electricity. This is off the table because converting another form of energy (coal or gas) into hydrogen involves an energy conversion, and in the process you lose energy.
If you want to burn hydrogen for transportation, then you have an energy storage problem. You also have a distribution problem because hydrogen is explosive and it makes metals brittle and it's very leaky.
How about nuclear? We've had it for a long time, but is it politically just too much of a lightning rod?
Chu: I hope that coal becomes more of the lightning rod. It should be. If you think about coal, it's really scary because it's our most abundant natural energy resource. And the countries that have the most are the most energy-consuming countries, namely us, China and then Russia in that order. It has sulfur dioxide and nitrous oxide and mercury pollution problems. In China, it's killing their people, its killing their infrastructure. And people die from mining it, so it's not a good energy source. We don't yet have proven technology to turn it into a clean burning fuel and capture the carbon dioxide and sequester it. We need to do a lot of research on that to make it economically feasible to do all that.
Is there much hope there? I've seen a few venture capital firms invest in clean-coal ideas, and a couple of companies, like BP, have sequestration projects going on.
Chu: Boy, it might have to be at least in the interim until we can get photovoltaic cells down by an order of magnitude or until we get the biomass up and running. We are going to have to have to do something in the next 50 years. The world will increasingly turn to coal and possibly nuclear. Even if you can sequester only for a few hundred years, it will buy time.
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