Switchgrass for Ethanol

Bio.org has a very interesting report: Growing Energy: How Biofuels Can End America's Oil Dependence (.pdf)

In it they talk about growing Switchgrass to create ethanol (and possibly some biodiesel). I had never heard of Switchgrass before. Basically it is a type of grass native to North America that grows to about 5-10 ft tall. Compared to using corn to create ethanol, Switchgrass would create much more ethanol per acre. It would require having a processing plant that convert cellulose to ethanol (see previous post).

The report states that with current technology, farmers could grow 5 dry tons/acre/year of switchgrass in the US. Current cellulose to ethanol conversion has a yield of 50 gallons (energy equivalence of 33 gallons of gasoline due to ethanol's lower density) per ton. One acre of switchgrass therfore yields 250 gallons of ethanol or 165 gallons of gasoline a year.

Switchgrass also has many positive environmental benefits as well. It causes less soil runoff, uses less fertilizer and has deep roots which sequester carbon below the ground. Also it is more friendly to birds and other animals than current crop fields.

This report then goes and makes some predictions which seem pretty audacious, but plausible given previous technology gains elsewhere. They predict that in the next 45 years we could increase yield from 5 to 12.5 tons per acre, and increase the output per ton from 105 gallons of ethanol from 50. So one acre would produce 1,312 gallons of ethanol. They believe this could be produced for $.39-.69 a gallon, and could then be sold to customers in a price range of a $1.00 a gallon.

They believe the US could create 108 billion gallons of gasoline from 114 million acres in 2050. That along with major increases in fuel economy would allow the US to be energy independent. 114 million acres is a big number (given that currently farm and rangeland in the US totals 700 million acres), but they believe that they can use 30 million acres that are currently in grass as part of the Conversation Resource Program. They also believe that land that is growing soybeans (73 million acres) for animals could be switched over as the switchgrass also produces a good amount of protein.

Not sure how realistic any of these assumptions are but to my novice eye it does seem plausible. And even if it doesn't get that far, it still can make a major dent in our energy imports and co2 emissions.