Could switchgrass offer a CO2 solution?
ADDISON COUNTY — When the American settlers first crossed the Great Plains, they encountered native species of prairie grass like switchgrass and big blue stem.
Now those same grasses — seeded deep in the American perception of a rural aesthetic — are being sown in Addison County fields in an effort to make them an affordable and viable source of local energy.
Switchgrass, which takes approximately three years to fully establish as a crop, is a net-zero carbon dioxide (CO2) source of energy. According to research conducted by Texas A&M University, switchgrass and other similar varietals sequester as much CO2 from the environment while growing as they emit while burning; some studies have found they actually capture more of the greenhouse gas than they emit.
A year ago, the Addison County Regional Planning Commission endorsed an application by Bennington-based Renewable Energy Resources Inc. (RER) for federal funds to create a mobile switchgrass briquette machine. The company’s concept is straightforward: It wants to work with Addison County farmers and larger local operations like schools, industrial buildings and towns to produce and consume a heating source — grass biofuel — within a 30-mile radius. Keeping the fuel source local reduces the costs and emissions associated with transporting fuel.
“Customers will be able to reduce their fuel bills by at least 50 percent compared to oil and know that the money they are paying for fuel will stay in the local community,” RER co-founder John Bootle claimed.
The company will pay approximately $72-$75 a ton for baled switchgrass, and it hopes to work with farmers to establish 3,000 acres on underutilized farmland and marginal swathes of land. The perennial crop, which yields three to five tons per acre, is harvestable using the same machinery that a farmer would use for hay, perhaps making it an appealing option for farmers that already have the equipment and the underused land.
Adam Lougee, executive director of the regional planning commission, wrote in his letter supporting RER that if the project is successful it would meet two goals of the regional plan:
• “To increase local energy production in an effort to move toward a less centralized and more reliable energy production system in the Addison Region.”
• “To have reliable, adequate and affordable energy that meets the needs of the region’s residents and businesses.”
Netaka White, bioenergy programs director for the Vermont Sustainable Jobs Fund, and Peter Carothers of Nash Farm started experimenting with a four-acre plot of switchgrass in New Haven last year. Since the crop needs to establish in its first year, they haven’t yielded any results, but White is highly optimistic about the energy capabilities of grass in the county.
DISPLACE FOOD CROPS?
While acknowledging the appeal of a renewable energy resources, some fear that biofuels could compete with food crops for farmland.
“There’s always a concern that biofuels and biomass will compete with prime farmland … and my own sense of it at this point is that the better soils, especially for a dairy farmer or a livestock farmer, are going to get a better return growing that forage for hay or silage versus biomass for energy,” said Sidney Bosworth, a University of Vermont professor of agronomy who has done extensive research on prairie grasses in Vermont. “So I think this (grass) fits into Vermont on that land that’s not being utilized for crops or it might fit into a rotation or just that less-than-ideal land.”
How much underutilized land does Addison County actually have?
Craig Miner, executive director of the local Farm Service Agency office, said he didn’t have a good answer for that. Bosworth said he believes there was not as much underutilized land in the county as in other parts of the state because farming is so important to the local economy.
Marie Audet of Blue Spruce Farm told the Independent that she doesn’t have room for a crop like switchgrass. She needs to use all of her land to raise feed for the Bridport dairy farm’s 1,300 cows. Still, she thought might work well for some farms.
RER’s Bootle, however, maintained that based on his company’s research, “There are thousands of acres of underutilized (Addison County) farmland that can be brought back into productive use that will generate income for farmers and other land owners, helping to stimulate the rural economy.”
Aside from local energy security, producing no net increase in CO2 and reducing transportation emissions, scientists say that local prairie grass systems offer some other environmental advantages.
Switchgrass might come in handy in Addison County for nutrient management. With long roots that stretch down about 12 feet into the soil, the grass is capable of absorbing high concentrations of nutrients like phosphorous that, if lead to massive blue-green algae blooms in Lake Champlain. The grass could thus be a profitable solution for farmers looking to contain runoff from their properties.
The long roots of switchgrass and other similar grasses also prevent soil erosion and form a strong riparian barrier along river edges as they stabilize banks. Furthermore, prairie grasses are a way to maintain open spaces. In an effort to preserve Vermont’s open swathes of land, residents might consider using these spaces for a biofuel that is aesthetically pleasing and acts as an excellent habitat for wildlife, especially birds.
Bootle also explained that switchgrass briquettes are more carbon neutral than wood chips and pellets.
“Switchgrass is truly carbon neutral since the CO2 emitted by burning in year one is absorbed when the crop is grown in year two, unlike wood since when a tree is burned it will take 30 years for a tree to re-grow and absorb the same CO2.”
RER does not recommend planting a monoculture of switchgrass, instead it recommends seeding a wide variety of prairie grasses.
“We would prefer to have lots of different types of grass because it’s more robust for preventing diseases,” said Bootle.
A stand of switchgrass can last for 15-20 years and requires minimal tending. The grass is harvested and baled once a year when the weather gets cold and the grasses’ nutrients have receded from the stems down to the roots.
Once the grass has been harvested, RER comes in. With $100,000 worth of federal funding approved by the sustainable jobs fund, RER has built a mobile briquette machine. The company’s plan is to bring the mobile unit to Addison County when there is grass to process. They will turn the switchgrass into little briquettes and sell them to larger commercial users for approximately $120-$130 per ton.
According to a USDA study, switchgrass has a net heating value of 14.4 million BTU per ton, compared with the 9 million BTU per ton that Middlebury College’s wood chips produce and the 13.6 million BTU per ton of premium wood pellets.
According to the Sustainable Jobs Fund’s White, “One of the factors that led to (RER’s) award was that they could show that they had prior success.”
In Benton, Pa., RER successfully launched a pilot project with a school that burned approximately three tons of grass a day to heat a 220,000-square-foot building during the winter. All grass used by the school was grown within a 15-mile radius, said Bootle.
But, there’s a hitch when it comes to burning grass — it has a high ash content.
“Anyone using a system strictly designed to burn wood pellets should (transfer to switchgrass) carefully and cautiously if they’re attempting to use 100 percent grass because of the high ash and the potential for minerals to fuse,” said White. “The reason that there’s a higher ash content in the grass fuels is that they have a higher mineral content than wood, such as silica and other ash-forming minerals.”
The remedy that RER has found for this problem is the use of a multi-fuel biomass boiler with an ash removal mechanism, like ones made by the company Skanden.
“The whole idea of using switchgrass is that it comes from a local area,” said Bootle. “The grass comes from a local area and is used within that local area.”
If RER can establish a network where it’s producing 8,000 tons of briquettes annually, they’ll establish a permanent briquette station.
For more information on RER, contact John Bootle at [email protected]. Reporter Andrew Stein is at [email protected].
CORRECTION 7/21/11: The spelling of Netaka White’s name in the cutline of this story was originally misspelled. It has been corrected.
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