Is ethanol the answer (3rd and final part)

In my two earlier posts on the benefits of ethanol, here and here, I concluded that corn-based ethanol was hardly a panacea. Using it in lieu of gasoline (or in gasohol blends) might somewhat reduce America's dependence on foreign oil, but the reductions would be small, and there would likely be little to no advantage to ethanol in terms of greenhouse gas emissions. The reason, primarily is that it takes large amounts of energy to produce ethanol from corn, and the sources of that energy tend to be non-renewable fossil fuels. Secondarily, significant substitution of ethanol for oil would require a huge re-structuring of land use in the country which would displace other crops and reduce the yield of corn per acre at the margin.

One question left to this final installment is whether other sources of ethanol would be more viable than corn. In particular, it is thought that ethanol could be produced in large quantities from switch-grass. Some studies have concluded that far less energy would be needed to grow and process switch-grass into ethanol than is required to grow and process corn. It appears that a substantial portion of the savings is due to the fact that switch-grass can be grown with far less need for fertilizers, which tend to be energy consumptive. Proponents of switch-grass ethanol (also referred to as “cellulosic” ethanol) believe that substantial reductions in greenhouse gas emissions could be achieved along with significant savings in petroleum consumption. Further, it appears switch-grass can be grown on land not suitable for many other forms of agriculture.

Unfortunately, it appears the technology to convert switch-grass to ethanol is not well developed, and at the moment I am rather skeptical about the estimates. This is partly due to my own ignorance, as I have yet to find and article that spells out in words I fully understand why switch-grass is so superior to corn as an ethanol source. It's hard for me to believe that the energy savings in the growing process can be large enough to make kind of differences projected, and I doubt that it is any easier to distill ethanol from switch-grass than it is from corn. Rather, I would guess it would be more difficult and energy-consumptive. But, that is not a fully informed opinion.

On the whole, I think it probably makes sense to dedicate some funds to further research on cellulosic ethanol, but I don't see any significant non-political reason to subsidize corn-based ethanol at all, much less at the current level.