On Sat, 1 Feb 2003, Bill Stewart wrote: > The big pollution issues with ethanol are in growing the corn, sugar, etc. > that's used to brew the stuff, fermenting it, and distilling it.
Ethanol from biomass is complete nonsense. So is biodiesel, given what fuel yield/m^2 is (can make sense for you personally if you have a lot of land, doesn't scale for the culture as a whole). You can make synfuel from biomass, though, there have been a few new processes (catalyzed, low temp) and reactor designs lately. There's a lot of cellulose and lignin out there. Ethanol sucks, but synmethanol has interesting synergisms. It is currently made from synthesis gas (which is mostly made from reformed natural gas, but can also be made from fossil (oil, coal, shale) or biomass, with hydrogen input) on a very large scale. Fossil fuel lobby goes in bed with the synmethanol lobby. Methanol has about half the energy density of gas, but it can be burned in ICUs (producing a cleaner exhaust), processed in onboard reformers and direct methanol fuel cells. Current fuel cells use platinum catalysts, but it is not fundamental to the principle. Methanol easily reforms to hydrogen and carbon dioxide, so it's your foot in the door of hydrogen economy. I'd say it's the best storage form of hydrogen for small mobile applications (planes and ships and large trucks excluding). > Even if it's grown "organically" (or at least without pesticides, > which is easier to do with corn that doesn't have to look good for market), > it's still a big issue with habitat destruction, and by the way, > have you ever smelled a brewery? :-) Ecoaudit of bioethanol is a desaster, period. > Photovoltaics, on the other hand, have all the wonderful toxic chemical > problems of the semiconductor industry. Solar thermal power sources Photovoltaics doesn't have to be done with semiconductor photolitho. Thin-film cells are deposited via plasma discharge in gas phase. Very interesting work is being done with polymer solar cells. The yield is not important, the half life is not important, but how much energy output from unit surface for a given price integrated over lifetime you can get. If your solar cell comes in rolls a buck/m^2 and lasts a couple of years in the desert lots of interesting things become suddenly possible. > are pretty well-behaved technology, though except for water heaters > they aren't very common.
