Utilities can meet state renewable portfolio standards—and reduce greenhouse gases—by burning biomass fuel. Whether utilities are prepared to jump into the biomass game, however, depends on how...
Repowering with Biomass
Waste fuels struggle despite coal’s decline.
finish in 2012. However, some things have changed. “When we started doing some of the final engineering on the technology that we chose, the prices ended up being higher,” Donovan says. “As a result, we had to go back to the Public Service Commission. They were unhappy with the price, so we are in the process of re-evaluating the technologies to see if there is a better alternative for us.” At press time Xcel was still hoping it can provide a recommendation to the PSC by the end of 2010, which would put the project a little more than a year behind schedule.
And if it does proceed, Xcel expects the cost to be higher than the original $60 million estimate. “We are hoping that we can find a technology with only a 5 percent to 10 percent price escalation,” Donovan says. “If it gets much above that, though, we would have some hard decisions to make.”
Regardless of what happens with the third boiler, Donovan emphasizes that the plant will continue burning biomass as the primary fuel in the first two boilers.
In 2008, Georgia Power completed an evaluation of converting an older coal-fueled power plant, Plant Mitchell in Albany, Ga., to burn wood biomass. The plant has one 155 MW coal-fired steam unit, and three 33 MW oil-fired combustion turbines. “The conversion is focusing on the 155 MW unit,” says Jeff Burleson, director of resource policy and planning. “We want to convert it to 96 MW of biomass.”
Georgia Power wants to switch for several reasons. Namely, biomass has lower emissions than coal. Also the utility wants to increase its fuel diversity to include more renewables. “It is also a cost effective way to generate electricity,” says Burleson. In fact, one of the utility’s initial reasons for looking at the switch was the increasing price of coal and projections for continued increases in the years to come. The prospect also offers local economic benefits, and in Georgia, the purchase of biomass fuel is exempt from sales tax, unlike coal and natural gas.
The utility doesn’t anticipate supply problems. Its research showed sufficient sources of wood biomass near the plant—which makes sense, because according to the Georgia Forestry Association, Georgia has more commercial forest land than any other state, with about 24 million acres. The company expects to obtain chipped wood waste fuel from logging operations within a 100-mile radius of the plant.
Georgia Power made its original appeal for the conversion to the Georgia Public Service Commission in 2008. “We have just filed an updated project plan with the Commission, including potential cost differences, based on the different technologies,” Burleson says. The utility also needs to get an air permit from the state’s Environmental Protection Division.
Original plans were to begin the transition in 2011 and have the conversion come on line in 2012. However, things were delayed in January 2010, with the utility waiting until the EPA better defines rules governing industrial boiler emissions. The anticipated industrial boiler “Maximum Achievable Control Technology” rule would regulate emissions of