NRG said the project could lead to commercial-scale projects using biomass fuels to reduce carbon dioxide emissions from other coal-fired plants.
NRG is planting 20 acres of switchgrass and sorghum at the plant site using seed and growing techniques provided by Ceres, a developer and marketer of high-yield energy grasses.
The switchgrass and sorghum were chosen for use specifically in Louisiana's soil and climate, and will be managed by a local grower.
The next phase, expected to be done next year, will use the biomass as a partial fuel for electric generation.
NRG shares fell 19 cents to $28.38 in recent trading. The shares have traded between $14.39 and $29.26 over the past year.
Princeton, N.J.-based NRG has generation capacity of 24,000 megawatts, enough to supply more than 20 million homes. Its retail business, Reliant Energy, serves more than 1.6 million customers in Texas.