NRG Energy Inc. had a bold experiment in mind in 2009 — burning switchgrass and sorghum along with coal at its New Roads power plant in what could lead this year to a full-fledged biomass program. The effort failed when the crops yielded only a fraction of the expected biomass, a company spokesman said.

“We planted a warm-weather variant of switchgrass, a cold-weather variant of switchgrass and the sorghum. The result was we did not get a usable crop,” NRG spokesman David Knox said.

NRG wanted to find out if the company could grow enough biomass locally to replace about 10 percent of the coal used to fuel Big Cajun II. The plant supplies power to more than 1 million electric co-op customers in Louisiana.

However, only the cold-weather switchgrass and the sorghum grew, Knox said, and the crops were only about 60 percent of what was expected.

Ceres Inc., a California seed company advising NRG, had said switchgrass can grow up to 9 feet high and yield 10 dry tons per acre. Ceres officials had said in 2009 the company believed it could double that production with seed engineering.

Ceres spokesman Gary Koppenjan said last month that the company could not comment because it was in a legally mandated “quiet period” that followed Ceres’ initial public offering of stock that was filed in May.

Michael Blazier, an LSU AgCenter associate professor in Calhoun, said weeds can overrun switchgrass in the first year of a crop because there aren’t good herbicides available.

The other issue with switchgrass is that there’s a wider than desirable variation in the time that the seeds sprout, Blazier said.

Blazier said he does not know which switchgrass was used, but the yield estimates mentioned appeared to be on the high end of the production scale.

Knox said for biomass to be an effective fuel, NRG needed a crop of consistent quantity and quality. The plants had to produce a consistent amount of energy; they did not.

Biomass supporters have touted switchgrass as an alternative fuel. The plant, native to the Great Plains, was said to have a wnumber of advantages. Switchgrass is a perennial, so it doesn’t have to be replanted each year, meaning less tractor fuel and fertilizer is needed. The plant grows on land that is considered marginal for farming and doesn’t require as much water. Unlike corn, switchgrass isn’t used for food, so burning the plant wouldn’t drive up grocery prices.

In 2009, NRG was bracing for an expected federal crackdown on carbon dioxide emissions. The company planted 20 acres of switchgrass and sorghum on its property in New Roads. NRG officials said if the pilot project proved successful, the crop could be expanded to 30,000 acres.

That would have included 1,000 of NRG’s own Big Cajun II acres, then add fallow land and some land now directed to sugar cane and soybeans to tie up long-term contracts that would be profitable to farmers within a 30-mile radius of the power plant. The opening this year of the new Mississippi River bridge between New Roads and St. Francisville would have given NRG access to land and growers on both sides of the river.

Big Cajun also was viewed in 2009 as the lead plant for a biomass program that, if successful, would move very quickly to Texas.

Big Cajun I and II produce around 1,900 megawatts of electricity a year. But the coal-fired plants also emit 14 million tons of carbon dioxide a year. If all went as planned, NRG estimated it could cut the emissions by 1 million tons a year by burning switchgrass and sorghum.

Unfortunately, Knox said, the crops weren’t usable.

“We’re still very, very interested in any avenue that we can to reduce our carbon emissions, of which biomass is one of the potential candidates,” Knox said. “If we have something that has a viable potential, we’ll definitely look at it, see if we want to try it.”

In the meantime, NRG is continuing a $300 million program to reduce mercury emissions at Big Cajun.