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Mixed prairie grasses are a better source of biofuel than corn ethanol and soybean biodiesel
National Science Foundation via SeedQuest
Diverse mixtures of native prairie plant species have emerged as a leader in the quest to identify the best source of biomass for producing sustainable, bio-based fuel to replace petroleum.
A new study led by David Tilman, an ecologist at the University of Minnesota, shows that mixtures of native perennial grasses and other flowering plants provide more usable energy per acre than corn grain ethanol or soybean biodiesel and are far better for the environment. The research was supported by the National Science Foundation (NSF) and the University of Minnesota Initiative for Renewable Energy and the Environment.
“Biofuels made from high-diversity mixtures of prairie plants can reduce global warming by removing carbon dioxide from the atmosphere. Even when grown on infertile soils, they can provide a substantial portion of global energy needs, and leave fertile land for food production,” Tilman said.
The findings are published in the Dec. 8, 2006, issue of the journal Science.
The is study based on 10 years of research at Minnesota’s Cedar Creek Natural History Area, one of 26 NSF long-term ecological research (LTER) sites. It shows that degraded agricultural land planted with diverse mixtures of prairie grasses and other flowering plants produces 238 percent more bioenergy on average than the same land planted with various single prairie plant species, including switchgrass.
“This study highlights very clearly the additional benefits of taking a less-intensive management approach and maintaining higher biodiversity in the process,” said Henry Gholz, NSF LTER program director. “It establishes a new baseline for evaluating the use of land for biofuel production.”
(8 Dec 2006)
Biofuel Skeptic Extraordinaire
An interview with David Pimentel
Tom Philpott, Grist
Q: You claim corn ethanol’s energy balance is negative, and there’s a growing consensus that it’s positive. Why the difference?
Pimentel: Pro-ethanol people make it out to be positive by omitting many of the inputs that go into corn production. For example, they omit the farm labor — I’m not talking about the farm family, I’m talking about the farm labor. They omit the farm machinery. They omit the energy to produce the hybrid corn. They omit the irrigation. I could go on and on. Anyway, if I did all of those manipulations, I could achieve also a positive return.
However, that’s not the way these assessments are made. You can go check the noted agricultural economists who have looked at corn as well as other crops, and they do include the labor, they include the farm machinery, they include repair of the farm machinery, and so forth and so on. And so, those are all inputs that the ag economists include. Why are the pro-ethanol people leaving them out?
…Q: All of that is very controversial, but let’s get to the really provocative part of your work. You claim cellulosic ethanol’s energy balance is “worse” than that of conventional ethanol. How can that be?
Pimentel: It’s quite easy. Number one, if you have a handful of sawdust, and a handful of corn, which one has the most starches and sugars? That’s easy. It takes almost twice as much sawdust to make the same gross energy as [corn] from cellulose, or wood.
Number two, it takes two additional treatments to release the starches and sugars [from cellulose]. That is, you’re going to treat the cellulose. It’s held by the lignin, and the lignin is the stuff that holds the trees up straight. And the cellulose is trapped inside that lignin. And you’ve got to release it, and that requires an acid or an enzyme. And so that’s one treatment, and then you’ve got to use an alkali to stop the acidity at some stage. And now you can introduce the bugs for the fermentation. But No. 1, it takes more cellulose, and No. 2, you’ve got two additional treatments.
…Q: So if we converted 100 percent of a year’s worth of solar energy stored in plant matter to fuel, we’d only supply half of our current energy consumption. What’s that telling us?
Pimentel: It’s telling us we’re using too goddamn much fossil energy! And another thing it tells us is that you’re not going to be self-sufficient, or even produce half of our energy from biomass in the U.S., if we want to eat. And that’s using an optimistic figure for ethanol production. I don’t know why [biofuel proponents] don’t sit down with pencil and paper and make these calculations instead of spouting off on all the wonderful things we can achieve.
…Q: A lot of earnest people support biofuels as a way to reduce greenhouse-gas emissions and displace fossil fuels. What do you tell them?
Pimentel: Conserve! One word. And no one talks about it, including the environmentalists. When these people talk about biofuels providing us with our energy, they need to look at the facts right now. Eighteen percent of all corn is going into ethanol production. We’re getting 4.5 million gallons of ethanol. That’s 1 percent of U.S. petroleum use. It’s 1 percent.
If we use 100 percent of U.S. corn, and we won’t do that, but if we used 100 percent, what would that do for us? Six percent. And ethanol is being subsidized at 45 times the rate of gasoline.
(8 Dec 2006)
The interview with Pimentel is part of a forum: Three perspectives on the biofuels debate. Other, more optimistic views:
Ana Unruh Cohen.
David Morris.
These opinion pieces are the latest articles in Grist’s special series on biofuels. -BA
Alternative-energy boom roils Asian environments
Patrick Barta and Jane Spencer, The Wall Street Journal via Pittsburgh Post-Gazette
Investors are pouring billions of dollars into “renewable” energy sources such as ethanol, biodiesel and solar power that promise to reduce the world’s reliance on petroleum. But exploiting these alternatives may produce unintended environmental and economic consequences — fallout that could offset many of the expected benefits.
Here on the island of Borneo, a thick haze often encloses this city of 500,000 people. The cause: forest fires that have blazed across the island, some of which were set to clear land to produce palm oil — a key ingredient in biodiesel, a clean-burning diesel fuel alternative.
…. Among other problems, the fires set to clear forest land spew millions of tons of carbon dioxide and other greenhouse gases into the atmosphere, experts say. In doing so, they exacerbate the very global-warming concerns biofuels are meant to alleviate.
Such side-effects aren’t an isolated problem. In Indonesia and Malaysia, forests are being slashed for new energy-yielding crops or other unconventional fuels. In India, environmental activists say, water tables are dropping as farmers try to boost production of ethanol-yielding sugar.
“Let’s be brutally frank: (The push for alternative fuels) is going to cause significant changes for the environment,” says Sean Darby, an equities analyst and expert on alternative-energy companies at Nomura International in Hong Kong. He is most worried about the strain on water resources caused by accelerated crop production. Water, he says, is “just as precious” as oil.
Some experts are also concerned that crops for biofuels will compete with other farmland, possibly driving up global costs of basic food production.
It isn’t clear how serious these problems will become — or whether they eventually will be resolved through new technologies and stricter environmental measures. Proponents of alternative energy, including palm-oil industry executives, say the dangers are exaggerated and are outweighed by the benefits new fuels promise.
…The alternative energy field “is almost like the Internet in terms of the pace of how fast all this is changing,” and new technologies could help resolve some concerns over collateral damage, says Chris Flavin, president of Worldwatch Institute, a Washington-based environmental organization.
(5 Dec 2006)
Typical good reporting by the from the “news side” of the Wall Street Journal. The WSJ’s editorial page on the other hand… -BA
