Monday, December 04, 2006

Grist Looks at Biofuels

If you've been scratching your head wondering what the difference is between ethanol, cellulosic ethanol, and biodiesel, Grist has a great rundown of what constitutes each biofuel as well as the pros and cons of each. In the end, Grist crowns cellulosic ethanol with the most potential, but until that biofuel becomes more of a reality, we'll stick with biodiesel:
Begun as a grassroots network of brewers that -- without subsidies or government regulations -- maintained a countercultural, anti-establishment aura, the biodiesel industry is rapidly turning mainstream. According to a recent article in the New York Times, about 76 commercial biodiesel plants are in production today, up from 22 in 2004. Even these can barely keep pace. Nationwide consumption of biodiesel tripled from 25 million gallons in 2004 to 75 million in 2005, and was expected to quadruple from that in 2006, reaching 300 million gallons. Accordingly, 50 new larger-scale plants are under construction.
Over its lifetime, pure biodiesel emits about 78 percent less CO2 than conventional diesel. Burning biodiesel also reduces emissions of smog-forming hydrocarbons and particulate matter by about 50 percent, and emissions of sulfur oxides and sulfates by 100 percent.

On the downside, all diesel engines -- whether fueled by conventional diesel or biodiesel -- still spew more toxic soot and smog-forming pollutants than gasoline engines, and this will likely remain true until cleaner "Tier 2" diesel emission standards go into full effect in 2009.
(R)esearchers at the University of Minnesota and St. Olaf College (Ed. note: my alma mater) recently found that biodiesel production is highly efficient, generating 93 percent more energy than is required to make it. They also found that biodiesel reduces greenhouse-gas emissions by 41 percent compared with fossil fuels. When Tier 2 emissions standards bring biodiesel up to par with gasoline and ethanol for air pollutants, biodiesel seems like it should be a no-brainer for green energy.

Definitely check out the article, as well as some corallary articles on the history of biofuels.

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At 11:06 PM, Anonymous Steve Savage said...

Yes, biodiesel is the most attractive idea today, but some simple calculations show that it could never be a very big part of the overall solution. Oil crops are just not productive enough. You are right that cellulosic is the real answer. If we are ever going to see energy independence we need 20-50 dry ton/acre cellulosic crops like Miscanthus or sugar cane

Steve Savage, Ph.D.


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