Ethanol is a hot topic these days. A few factors contribute to that, but I like to highlight a behind the scenes one: Congress has approved a tax credit of 0.51 cents per gallon of ethanol used as motor fuel (with a mandate of 7.5 billion gallons of “renewable” fuel used by 2012). Maybe that explains Chevron’s site WillYouJoinUs.com or BP and Dupont joining forces to develop “biobutanol”.

Professor Kammen’s (DtaS’s May speaker) group has been studying the effect of increased ethanol use. At the time of the study, ethanol constituted 99% of all ethanol production.

Here’s the big debate: Does ethanol take more energy to produce than it provides? Also, what’s the relative green house gas emissions from a changeover?

His group developed a bio-fuel analysis model (EBAMM). Essentially, its hard to just measure the efficiency of biofuels purely on net energy. There are other systemwide effects, including greenhouse gas emissions, “waste” product utilization, etc.

I’ll get to the point. Here are the findings based on 3 cases (energy in vs energy out is I’ll call energy ratio - ER)

Gasoline production right now:
1.1ER petroleum + 0.03ER Natural gas + 0.05ER Coal…94 g CO2 produced/fuel unit

Ethanol Today (corn based ethanol with not many changes):
0.04ER petro + 0.28ER nat gas+ 0.41 coal…77 g CO2 produced/fuel unit

CO2 Intensive (let’s ship corn from NB to a coal fired power plant in North Dakota):
0.18 petro+0.05 NG+0.66 coal….91 g CO2 produced

Cellulosic (using switchgrass assuming it becomes viable):
0.08 petro + 0.02 NG + -0.02 coal….11 g CO2 produced.

Basically, IF cellulosic becomes viable, huge reduction in CO2 emissions with little petro use. The let’s ship from nebraska to north dakota plan is ludicrous, but I bet it makes a bunch of people rich. And if we continue to push the current plans, we get some reasonable effects.

After reading through this study, I’m left with some major questions/comments:
1. Why are we pushing corn-based ethanol if the science says it isn’t the best technology?
2. Ethanol seems to provide large scale benefits in terms of “lessening our dependence on foreign oil” (that phrase courtesy of Karl Rove).
3. Our strategy of having a large power plants doing all the work yields the worst result. How does power generation decentralization play into this issue?
4. Switchgrass……Let’s talk more about switchgrass. What’s in the way of it becoming economically viable?

For more about Prof Kammen’s study, check out the EBAMM site.