Farmers may be able to produce more switchgrass — and thus make cellulosic ethanol production more economically viable — than previously expected.

Ceres Inc., an energy company based in Thousand Oaks, Calif., says average yield figures often used by academics and policymakers to forecast bioenergy economics and environmental benefits might be too conservative.

In a press release, the company reported yield results from its nationwide network of field trials. Average biomass yields for switchgrass varieties tested last season were as much as 50 percent higher than the government’s projected yields for 2022.

It said its Blade Energy Crops brand proprietary varieties averaged nearly 10 tons per acre. That could mean policymakers will likely need to rethink assumptions regarding energy crop production. A number of studies assume switchgrass yields as low as 2 to 4 tons per acre and many hold that yields will be virtually flat into the future.

Ceres CEO Richard Hamilton says that, while Ceres needs additional data before formally proposing new benchmarks, the “writing was on the wall. These results are not surprising when you look at the impact utilizing modern biology has had on food crop yields, like corn, which has seen a five-fold increase since the first hybrids were introduced.

Researchers at Auburn University say their test plots have produced the equivalent of up to 15 tons of dry biomass per acre. The five-year average for the plots is 11.5 tons per acre, which could produce up to 1,150 gallons of ethanol per acre.

The University of Tennessee and Auburn are conducting extensive research on switchgrass through a partnership with the Department of Energy’s Oak Ridge National Laboratory in the development of a pilot cellulosic ethanol plant.

The University of Tennessee is working with a group of farmers to produce switchgrass in a 50-mile radius of the plant in Vonore, Tenn. Participants in the program harvested 723 acres of switchgrass in 2008. UT’s Biofuels Initiative aims to have 2,000 acres of the switchgrass planted in 2009 with an eye toward 6,000 acres eventually.