----- Original Message ----- From: "Dan M" <[EMAIL PROTECTED]> To: "'Killer Bs (David Brin et al) Discussion'" <brin-l@mccmedia.com> Sent: Friday, January 11, 2008 11:24 PM Subject: RE: Take that, Iowa!!
> > >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On >> Behalf Of Jim Sharkey >> Sent: Thursday, January 10, 2008 4:08 PM >> To: brin-l@mccmedia.com >> Subject: Take that, Iowa!! >> >> >> I'm sure some of you knew this, what with your big brains and all, >> but I found it interesting: >> >> http://www.sciam.com/article.cfm?id=grass-makes-better-ethanol-than-corn >> >> _Scientific American_ is saying grass as a source of ethanol has >> the >> potential to be vastly more efficient than corn. Pretty cool >> stuff, >> I think. > > I've been busy, but I'm sorta back. > > Unfortunately, when the numbers are crunched, it doesn't look very > good. I > have a blog on the Scientific American website that looked into the > fundamental numbers. > > I looked at 2006 numbers for a baseline. I didn't include the > energy price > of ethanol, so these numbers overstate the viability of ethonal. > > In 2006, 4.9 billion gallons of ethanol were produced. That's a > yield of > about 2.3 gal/bushel.a bit lower than the estimate I gave. 4.9 > billion > gallons of ethanol replace 3.3 billion gallons of gasoline.or about > 2.4% of > gasoline consumption. 100% of the crop would give 5x that amount, or > 12%. > That's slightly less than the 13% I estimated earlier.which means > that the > 2.6 gallons/bushel was a bit optimistic. > > These yields are for a high density crop usually grown on the best > land with > intense cultivation. I cranked the numbers for switchgrass, and the > nominal > yield of ethanol per acre on cultivated land is less than half of > that of > corn. It still might be better, due to a lower energy costs for > production, > but it won't be better than my analysis which ignored the energy > cost of > ethanol. > > In 2006, the US had about 320,000 sq. km of the best farmland > dedicated to > corn. In 2002, the US had about 1.760 million sq. km cultivated in > all > crops (I couldn't easily find 2006 data for the total..but 2002 > should give > order of magnitude). The total land area of the US about 3.8 million > sq. km, > of which about 0.5 million is in Alaska, which I will not consider > potential > crop land. So, most of the Continental US and Hawaii is already crop > land...so there is not a lot of land just waiting to be used. Some, > like > the SW desert and the mountains are virtually impossible to use, so > it is > very difficult for me to see how any significant contribution to our > energy > supply will be afforded by ethanol. > > Then why the subsidy? Two words: farm lobby. > I agree with you on almost every point here, especially when you point out the farm lobby. There are aspects of the American ethanol industry that are quite problematic. And I think most would agree that supplanting food crops to enhance energy production is a pretty bad idea. As I understood the original switchgrass proposals made a few years ago, switchgrass was supposed to be grown in addition to and not instead of other crops. The reason this was proposed was that switchgrass (and several other hardy grasses) would easily grow in areas considered marginal to poor (or worse) for other crops. Grasses could be grown on highway right-of-ways or to prevent erosion on hillsides and riversides. It would grow in swamps. It could even be grown in fallow fields if the need arose. Our fuel standard is currently E15 and moving toward E85, but I have not seen any proposals for E100. So I don't think this will be a long term problem/solution. Hopefully, we will have better alternatives in just a few years and won't have to burn anything more complex than hydrogen to move us and our goods around. Like this from the Wikipedia article for Gallium: "Aluminum is reactive enough to reduce water to hydrogen, being oxidized to aluminium oxide. However, the aluminum oxide forms a protective coat which prevents further reaction. When gallium is alloyed with aluminum, the coat does not form, thus the alloy can potentially provide a solid hydrogen source for transportation purposes, which would be more convenient than a pressurized hydrogen tank. Resmelting the resultant aluminum oxide and gallium mixture to metallic aluminum and gallium and reforming these into electrodes would constitute most of the energy input into the system, while electricity produced by a hydrogen fuel cell could constitute an energy output. The thermodynamic efficiency of the aluminum smelting process is said to be approximately 50 percent. Therefore, at most no more than half the energy that goes into smelting aluminum could be recovered by a fuel cell. " Interesting stuff. xponent Land Use Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
