Re: SC18

http://www.washingtonpost.com/wp-dyn/content/article/2006/06/30/AR2006063001480.html

The False Hope of Biofuels
For Energy and Environmental Reasons, Ethanol Will Never Replace Gasoline

Biofuels such as ethanol made from corn, sugar cane, switchgrass and other crops are being touted as a "green" solution for a large part of America's transportation problem. Auto manufacturers, Midwest corn farmers and politicians are excited about ethanol. Initially, we, too, were excited about biofuels: no net carbon dioxide emissions, reduction of oil imports. Who wouldn't be enthusiastic?

But as we've looked at biofuels more closely, we've concluded that they're not a practical long-term solution to our need for transport fuels. Even if all of the 300 million acres (500,000 square miles) of currently harvested U.S. cropland produced ethanol, it wouldn't supply all of the gasoline and diesel fuel we now burn for transport, and it would supply only about half of the needs for the year 2025. And the effects on land and agriculture would be devastating.

It's difficult to understand how advocates of biofuels can believe they are a real solution to kicking our oil addiction. Agriculture Department studies of ethanol production from corn -- the present U.S. process for ethanol fuel -- find that an acre of corn yields about 139 bushels. At an average of about 2.5 gallons per bushel, the acre then will yield about 350 gallons of ethanol. But the fuel value of ethanol is only about two-thirds that of gasoline -- 1.5 gallons of ethanol in the tank equals 1 gallon of gasoline in terms of energy output.

Moreover, it takes a lot of input energy to produce ethanol: for fertilizer, harvesting, transport, corn processing, etc. After subtracting this input, the net positive energy available is less than half of the figure cited above. Some researchers even claim that the net energy of ethanol is actually negative when all inputs are included -- it takes more energy to make ethanol than one gets out of it.

But allowing a net positive energy output of 30,000 British thermal units (Btu) per gallon, it would still take four gallons of ethanol from corn to equal one gallon of gasoline. The United States has 73 million acres of corn cropland. At 350 gallons per acre, the entire U.S. corn crop would make 25.5 billion gallons, equivalent to about 6.3 billion gallons of gasoline. The United States consumes 170 billion gallons of gasoline and diesel fuel annually. Thus the entire U.S. corn crop would supply only 3.7 percent of our auto and truck transport demands..........


Using the entire 300 million acres of U.S. cropland for corn-based ethanol production would meet about 15 percent of the demand...........


The above of course, is not even remotely realistic, but if you could do it, achieve 15 percent, in Bush's Energy Dreamland, then all we would have to figure out is where we were going to grow all our food, what to feed all the animals we eat, and forget about food export income, among other things. The rest of this article is worth the read.