George:

Valerie L'Herrou falls into the same trap that other corn ethanol critics stumble on: using the weakness of corn to discredit bio fuels in general.

She makes one important point though - we will not change the slide into irrevocable climate change without changing our lives. Even nuclear power will not fill in for all the energy we waste.

Let me answer a few of her points:

1. The energy in, energy out numbers for different fuel types include all the harvesting, fertilizing, processing and delivery to the end user costs. Corn ethanol yields about 25% more energy out than in; cellulosic ethanol from switchgrass, about 300% more. That is significant.

2. Bio-fuel does emit CO2 when burned (as it does when it decomposes naturally) but it also takes up CO2 when it grows. This "closed cycle" means that there is no net gain in CO2 to the atmosphere. Fossil fuels, however, release CO2 stored for millennia into the atmosphere - or "open cycle" burning.

3. Valerie did recognize one value of switch grass (or, more broadly, native warm season grasses-NWSGs) in that they are perennials. But there is more. If harvested after dormancy virtually all of the active nutrients will have returned to the roots, requiring then almost no additional soil amendments. (This is not the case if they are harvested green for fodder.) NWSG's also sequester CO2 in their root systems - about 1 ton per acre per year. Growing NWSG's for fuel will then actually reduce the earth's total carbon load.

4. The food issue is, I believe, a major red herring. The tortilla crisis in Mexico was due to farmers there going out of business because they could not compete with cheap US corn flooding their markets because of NAFTA. When ethanol use drove up US corn prices, there was no Mexican fallback supply. (This distortion of the Mexican farm economy, by the way, has been a major impetus to the flood of unemployed workers moving North.) Experience showed in India, for example, that when cheap US food aid no longer made it impossible for Indian farmers to compete, they did. Today India is virtually self sufficient in food.

5. The fact is, though, that we can grow 30 billion gallons of cellulosic ethanol on the 30 million acres of CRP land now set aside for no harvestable crops. This land can be planted in NWSG's which will meet the conservation goals as well as provide feed stock for fuels.

Even ethanol, from any source, is a transition fuel. Next will probably be butanol going into rechargeable hybrids where the electricity is produced by ultra clean coal burning plants using carbon sequestration, and wind, solar, hydro and nuclear power. I also think there is a great future for electricity production from biomass. Before that happens, though, we will have to make major changes in the way we sprawl, travel, commute, heat, cool and produce. As long as ethanol is touted as the way to avoid the real changes we will have to make then Valerie is dead right: it is a pipe dream.

Al Weed (Electronic mail, June 29, 2007)