> -----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. Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
