NRG evaluates biomass potential in Louisiana

By Lisa Gibson
Posted October 16, 2009, at 8:43 a.m. CST

NRG Energy Inc. has begun a pilot-scale biomass growing project at its Big Cajun II electrical generation site in Louisiana that could result in commercial-scale biomass use by the company.

A 20-acre plot was seeded with switchgrass and high-biomass sorghum at the recommendation of Ceres Inc., a developer and marketer of high-yield energy grasses. The choices were made after careful consideration of the environment, climate and soil types in the area. "We worked closely with Ceres and these are the two they recommended," said Dave Knox, communications director for the company. The plot will be managed by a local grower.

In phase one of the project, NRG will evaluate how well the crops grow, followed by a second phase, scheduled to begin in 2010, where the biomass will be used in the Big Cajun II boilers. The company will determine if it's effective and in phase three will decide if and how to expand, Knox said. The growing phase could continue through phases two and three, he added, as the company might expand the project to more types of crops, depending on the success of the switchgrass and sorghum.

An expected biomass yield for the planted crops has not been determined, Knox said, as the plot is relatively small, and phase one is not intended for high outputs. "It's not designed to give yield for burning," he said. "It's designed to give yield for evaluating."

Once established, switchgrass requires little or no tilling and minimal nitrogen fertilizer and other crop inputs. It will be harvested into bales, dried and shredded before being fed into the combustion chamber of the plant.

Currently, NRG's plants run on coal, but the company also is looking into biomass fuel for its Somerset, Mass., plant. The U.S. DOE has chosen the company's gasification project to proceed into the due diligence phase of the DOE Loan Guarantee Program, according to the company. NRG applied for a $158 million loan guarantee for the proposed 112 megawatt facility, which could power up to 100,000 homes, according to the company.

"We are looking at a lot of initiatives through low- and no-carbon generation," Knox said. "We are very interested in how we can move forward and reduce our carbon intensity." NRG is considering the use of wind, nuclear and solar power, among several others, he added.