January 27, 2006
Interesting timing: this study (subscription only, except for the abstract), just published in the journal Science, may give a boost to the biofuels bill that's currently working its way through the Washington legislature.
The study addressed itself to the issue of whether ethanol from corn really reduces greenhouse gas emissions -- which has been an area of fairly intense interest among both supporters and skeptics of biofuels.
To me, it looks like the authors really did their homework, and have done their best to be conduct a fair analysis that takes the best points from all sides of the debate. Their final answer: compared with gasoline, filling your tank with corn ethanol reduces total GHG emissions by about 13 percent. Score a point for ethanol!
As fair as the paper seems, it probably won't end the controversy; David Pimentel, one of corn ethanol's main detractors, has already dismissed the study as "another pro-ethanol paper".
And, as with everything, the devil's in the details; and for a system as complicated as corn ethanol production there are a lot of details. For example -- and pardon me if this is getting too geeky -- I'm not sure whether the authors accounted for the 1 percent or so of nitrogen fertilizers that are applied to cornfields, but then get volatilized and released into the atmosphere as nitrous oxide. NO2 is a potent greenhouse gas, about 310 more powerful at trapping heat than carbon dioxide, so even small releases can make a difference. If the authors haven't accounted for that, then the GHG gains of ethanol may be substantially lower than the paper suggests -- perhaps a 3 percent improvement rather than 13 percent.
But one thing that the paper does make clear is that cellulosic ethanol -- made from woody material or straw -- at least has the potential to be lead to really substantial reductions in GHG emissions. If a modest biofuels bill can help jumpstart interest in cellulosic ethanol, it seems like it could be well worth the effort.
Posted by ClarkWD | Permalink
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I don't doubt that alternate fuels are destined to replace petroleum-derived fuels. But, I must point out that their most efficient combustion is achieved in the Parallel and Plug-in Hybrid drivetrains. Don't lead people on by omitting the critical difference that the Hybrid application makes. Burning bio-diesel in a standard engine means nothing, NOTHING, compared to the potential of the true Hybrid vehicle. I mention 'true hybrid' because GM's Silverado and Saturn VUE and even the Honda hybrids are NOT true hybrids. Their potential is miniscule compared to the Prius and Ford Escape Hybrids. And another thing: the hydrogen fuel cell car is a hoax. And GM's 'drive-by-wire' and 'in-wheel' electric motor technologies are also a hoax. When GM goes bankrupt as expected, we should not bail them out. Their cars are crap and planned obsolescence!
Posted by: Sirkulat | Jan 29, 2006 12:35:33 PM
Sheesh, I had a post on this already to send in, Clark, and you beat me to it. Shoulda checked before I wrote it :o)
I guess this means a long comment is coming, eh?
Here's a link to the entire paper:
From this website with more information on the project:
I read this article as finding that ethanol from crops and residue yields net energy (compared to consuming more energy to produce than it yields), but that expanding ethanol production will require more sustainable agricultural practices to reduce negative impacts on the environment, including fertilizer runoff and emissions of greenhouse gases through fertilizer production and application and product delivery.
These findings are important because they reduce uncertainty in our knowledge regarding impacts of a new technology, and they allow us to discuss whether we are going to reduce area committed to food production when there is a likelihood that we will have 3 billion more people on the planet by 2050. Having 3 billion more people demanding resources will require societies to devote an additional 1 billion hectares (3.9 M sq mi. ) of arable land. If we reduce the amount of area dedicated to food and instead dedicate it to our energy demands, we have to find new ways to feed these new mouths.
Complicating this issue is our knowledge that societies do not change direction overnight.
Posted by: Dan Staley | Jan 29, 2006 3:36:48 PM
The fuel vs food argument is not as clear cut as you would think.
For example, the majority of the corn production in the US is used for cattle feed to provide meat (predominately grain fed beef). Cornmeal left over from ethanol production can be used to feed cattle as well which provides a better overall use of the material. This also applies to other crops used for the production of biofuels (such as soyabeans and canola).
Two other factors are important to consider;
1. Corn and soyabeans are two of the lowest yeild crops for biofuels. Other crops such as canola, mustard, sugarcane, sugarbeet, etc. have far higher yeilds and therefore need less land per gallon of fuel.
2. Shifting away from a high meat diet (particularly grain fed beef) enables a much better food yield from land and can provide food for more than seven times as many people.
Posted by: Mike | Feb 3, 2006 6:37:36 PM
Mike, the intake of protein from animals is a key indicator of wealth in a society. That is: as soon as people reach a particular income level, they begin to consume meat. This is a powerful social factor to overcome, hence my concern for 'burning food' (even cow's food) - you don't change societies overnight and meat consumption will expand as long as we strive to bring more people out of poverty.
And I agree also that other plants yield more energy/acre, but the corn lobby has a hold of this one. I'd prefer use of a plant that doesn't need irrigation and can mitigate some saline soil at the same time.
Posted by: Dan Staley | Feb 6, 2006 2:38:09 PM