Are Switchgrass' Days Numbered?
by Jeremy Elton Jacquot, Los Angeles on 09. 3.07
Move over, switchgrass: there are some new grasses in town gunning for your biofuel crown. Researchers at the University of Northern Iowa's Tallgrass Prairie Center (TPC) are looking at ways to use the state's mixed prairie plantings as a source of renewable energy — as biomass to produce ethanol or to burn for electricity. "When you hear about biomass, you usually hear only about switchgrass, but we're looking at using prairie plants including wildflowers," said Dave Williams, manager of TPC's Prairie Institute.
A study conducted this past year by David Tilman, an ecology professor at the University of Minnesota, had demonstrated the potential for polycultures of multiple grass, prairie and wildflower species to serve as an alternative to switchgrass in producing ethanol. Tilman and his colleagues found that, in addition to producing more than twice the biomass than single-species planting (not less than 238% more than switchgrass), multiple-species plantations restored biodiversity, grew on degraded land and — perhaps most importantly — could be carbon negative. Biofuels derived from this source could also store up to 51% more energy per acre than corn.
Because Tilman's study was only conducted on small, hand-weeded parcels of land, researchers at the TPC plan on expanding its scope to make the results applicable to local farmers, who commonly use hundreds of acres. Daryl Smith, the director of the TPC, believes that using the multiple species plantings on sandy, marginal agricultural land could yield several benefits, not least of which would be reducing soil erosion and creating better habitats for wildlife.
The researchers are particularly interested in seeing how the prairie grass stands sustain harvest — in other words, if they will need to be burned down less or if certain parts of the stand will only need to be harvested every year in rotation. They will also convert the plantings into pellets and cubes to examine their potency as a new source of fuel. The TPC will collaborate with Cedar Falls Utilities (CFU) to test how much electricity could be generated by burning large amounts of the biomass.
Smith estimates that 100 acres of the mixed prairie plantings could provide enough fuel for an 8-hour test burn at one of CFU's facilities. Bill Dotzler, a state senator who helped the TPC gain the necessary initial funding, is hopeful about their potential: "You almost get a trifecta with this --- you clean the streams, you provide habitat for pheasants and other wildlife and you produce an alternative fuel ... It's not going to be the whole answer, but I think burning the native plants could be an important part of the whole puzzle."
Via ::The Waterloo-Cedar Falls Courier: Center researches grass as fuel (newspaper), ::Biopact: Tallgrass Prairie Center to implement Tilman's mixed grass findings (blog)
See also: ::Bait and Switchgrass, ::Prospecting for Biofuels
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"burning the native plants could be an important part of the whole puzzle."
How about not burning anything anymore? We've had fire long enough to not be obsessed with it any longer. Internal combustion, coal power, natural gas and oil heat are all the same: they are all just a bunch of people playing with fire. Let's advance to the next age, whether it be playing with wind or with sun, or the Earth itself through geothermal energy. Let's advance beyond creating habitat just long enough for wildlife to move in, then cutting it down and burning it. How many pheasants will die in harvest?
Seriously, we can do so much better.
Bit of an irony here. Native tall grass prairie in the US was sustained by wildfire, set either by Native Americans as a hunting technique or by lightning.
What a more hopeful future for biofuels than the ecological disaster that corn-based ethanol would be! We would, for the first time, get beyond the monoculture mentality that agribusiness would like to see used in ethanol. While better than corn, endless fields of monocultured (not to mention bioengineered) switchgrass would not be far away if we commit to a single plant type for our energy needs. Developing pheasant-safe harvesting tools will be a breeze compared to figuring out the chemistry! This technology would have the potential of taking huge swaths of the Great Plains prairie, which people had no place plowing up in the first place, back to their natural role of sequestering CO2, preventing erosion and building soil, all while displacing at least some of the fossil fuel used to power our cars... Wind, solar and geothermal certainly do have roles to play, especially in powering the grid, but for the ethanol debate this is real progress!
Amen sheepguy
This is such a seductive idea, and it has to be a good way to go, if the energy balances stack up. It would be great if it is possible to mow down the prairie, leaving the roots and other biomass to protect the soil. It would also get away from the need for fertilizers (the US is structurally short in fertilisers and imports come from the Caribbean and Canada) . We might even see herds of Buffalo sweeping majestically across the plains, wildlife and so on.
I'm a little confused... the article begins saying that the prairie grasses would be the substitute feedstock for cellulosic ethanol production, and ends say that they're going to just combust it for electricity. Anyone else catch that, or know which it is (or both?)?