Jun

8

As to the hydrogen production issue, doesn't it shift our reliance to coal, instead of oil? Yes, its domestically sourced, but also beset with similar (worse?) carbon emission issues as petroleum…

Michael Ott replies:

Mike OttHydrogen can be produced from coal, but it's very nasty to the environment and will eventually run out. Biomass is a much better source because it's renewable and available in massive amounts (1.3 billion tons per year, according to the USDA). Biomass can be converted into both liquid and gaseous fuels and will be the bridge to the hydrogen economy. This is why funding ethanol research is important. First you make it from something easy, like starch found in corn or sugar cane. Then you make it from something available in much larger amounts like wood, corn stover, or other ag residues.

One of the main advantages of making ethanol from corn is that the logistics for storage and transport are well established. Plus there is a lot of sugar which can be easily accessed by existing enzymes. The logistics of moving around large amounts of biomass are not well known and will require large amounts of infrastructure. It will be built because infrastructure is always built to support a better and cheaper fuel source. Cellulosic enzymes are also getting better, improving 30X in the last 5 years. The same infrastructure will be used for gasification of biomass, which will produce the massive amounts of hydrogen needed to drive an economy.

This is why I'm optimistic about biomass. Currently, you can make about 80 gallons of ethanol/ton, so the potential productivity is 104 billion gallons. The US consumed 142 billion gallons of gasoline last year, so there is potential to replace a significant chunk of gasoline. Assume that efficiencies will increase to 100 gallons/ton and that dedicated energy crops provide 1.5-2 billion tons/yr, and theoretically all gasoline could be replaced. Obviously not all will be converted, but the potential is there.

Addressing Stefan's points about energy efficiency — Assuming that the sun's energy is free (which it is because it will shine the same on a parking lot as a cornfield), the efficiency of ethanol is 1.4 : 1. Gasoline is 0.88 : 1. The economic efficiencies are much more important. Right now ethanol is much cheaper to produce than gasoline and will be competitive down to $40-50/bbl oil. Both ethanol and gasoline are heavily subsidized, so economic arguments are tough to make. If all subsidies and credits were removed, ethanol and oil would be roughly equally priced at $30/bbl (maybe a little higher due to recently raised corn and nat. gas prices).


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