interview > greene > greene 6

Greene 6 (1:35)
Topic(s): Biofuels / Future Transport
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We now consume about 6 billion gallons—I should probably check the number, but I think it's about 6 billion gallons of ethanol every year, which is of course biofuel and there's much talk about increasing the amount of biofuel dramatically. But in my own view, there's no sense in doing that unless we get away from corn-based ethanol, and we produce our ethanol from forest residues and crop residues and other cellulosic material that should be cheaper and should be more efficient and produce much less greenhouse gases than corn-based ethanol. So if we can do that, we have already the technology for using ethanol in vehicles.

We may decide that ethanol is not the best fuel to make out of biomass. There're other options. And some of these options have better properties, better energy density, but the process for producing them is not yet commercial. So I think we'll need to find better ways of making fuel out of biomass than we have now. And then biomass can become a more significant source of energy. But there—it's impossible essentially to fuel the transportation system entirely with biomass. There's simply not enough of it, and we need a lot of it for food. So that's not going to be the solution, but it's going to be part of the solution, I think.