TR: But relying heavily on biofuels could have unintended effects, such as raising food prices. Unless we understand the overall system, the things we try to do to make things better …
GW: … can make things worse.
Cellulosic ethanol has some good features. But it has all sorts of problems. We don’t know what the energy costs are of doing this. You need some energy to collect the stuff, and to do the processing and to distill the fluids. There’s the question of whether we really can make large quantities of it. It’s seasonal. You can only do it in parts of the country. You have to then think about taking this relatively low-energy thing, biomass, and collecting it to a central processing station. You can’t afford to ship this stuff over large distances, which means the processing plants are small and intrinsically inefficient for large-scale production. And should we think of topsoil in Iowa as a renewable or a nonrenewable resource? We think about the problem of depleting petroleum reservoirs, but what about the problem of depleting Iowa topsoil? We don’t know how this set of energy technologies all fits together. How do we do agricultural energy production, and how do we think about agricultural land overall–for example, the competition of energy with food production, and just the mere fact that the soil can wear out if it’s not managed correctly?
TR: So what is the solution?
GW: We need long-term investment. We need new ideas. We need a cadre of young people to work on it. This is not a Manhattan Project. It’s not something in which we have a single engineering objective and if we can solve that, the mission is accomplished. It’s going to have a large number of components: Understanding photosynthesis. Understanding how to most efficiently make solar cells. Making hydrocarbon-fuel combustion more efficient. Making energy transmission more efficient. Understanding how the pieces work together so that if we do this, we know we’re not actually going to make the situation worse.