Thursday, April 9, 2009

Cellulosic Ethanol and Wood...

I was reading this article about the "Q" bacteria discovered by UMass at the Quabbin with the potential to be an efficient convert of cellulose to ethanol.

Let's do some quick math.

-- Estimates are we can get 94 gallons (eventually) of ethanol from each ton of cellulose.
-- Cord of hardwood is roughly 1 ton per cord.
-- Connecticut forests generally have a sustainable yield of 1/2 cord per year
-- There's 1.8 Million acres in Connecticut
-- About 60% of Connecticut State Forests are loggable. The rest are environmentally sensitive, culturally sensitive, or being purposely managed "naturally." I think we can apply that percentage to the state as a whole.
-- So that's 1.08 Million acres yielding 1/2 cord per year which would make 25 Million gallons of Ethanol in a year.
-- In 2007 Connecticut used 37,906 thousand barrels of gasoline, that's 1,592,052,000 gallons of gasoline (that's 530 gallons per person, about 10 per week, so I believe it).
-- Ignoring ethanol's lower energy content (long term that could be compensated for by more efficient, higher compression engines), Connecticut grows enough wood to offset 1.5% of it's gasoline usage.

I have no doubt cellulosic ethanol can be part of the solution, but obviously it ain't the end of the world. If we assume similiar figures for Maine (in reality, they'd probably harvest a higher percentage, but growing a little bit fewer tons per acre) they'd be around 240 Million gallons of ethanol a year, or roughly enough to displace 1/3rd of their state's use of a gasoline.

And we haven't talked about diesel.

Switchgrass can produce about 5 tons per acre, but at what cost in annual fertilizers and pesticides I don't know. It shouldn't need fertilizer and pesticide like corn, but I doubt it can go without any perpetually.

No comments: