Georgia Power wants to shut down three power plant units within the next two years, an official from its parent, Southern Co., said Monday.

The utility intends to close one unit at Plant Branch in Milledgeville by October 2013 and another one by December. Jeff Burleson, a vice president with Southern, told the AJC the company also wants to shutter an additional unit but would not specify what type of fuel. He also would not name the power plant that would be impacted.

The decision to shutter the coal-fired units is based on the pending Environmental Protection Agency rules that would require the utility to install equipment to meet stricter environmental controls, the company has said. It would be too costly to upgrade the Plant Branch units, which started operating in 1965 and 1967.

Additionally, Georgia Power plans to cut an additional 2,600 megawatts from its system through energy-efficient programs, said Greg Roberts, vice president of pricing and planning. It will do this by promoting more energy-conservation or "demand-side management" programs, he said.

Roberts announced Georgia Power's plan to reduce demand on its system at the Georgia Renewable Energy Forum, sponsored by the state's Public Service Commission. The meeting, held at the state Capitol, reviewed what types of fuel Georgia Power uses as well as how readily available are renewable fuels such as solar, wind and biomass.

Georgia Power currently gets about 5 percent of its fuel from renewable sources, Burleson said. The company said last month it would buy up to 50 megawatts of solar power by 2015 to comply with a request from state utility regulator Lauren McDonald to add more of the alternative fuel to its energy mix. One megawatt has the capacity to power 400 homes or 1 one Super Target store.

Georgia Power will file this information as part of a long-term energy plan with the PSC at the end of the month. The utility said earlier this year it would consider shutting down Units 1 and 2 at Plant Branch but had not mentioned closing an additional coal-fired unit.

The PSC requires Georgia Power to have a 15 percent reserve margin of power on its grid. Burleson said that the utility's margin is "well above" that, and will be even after the coal-fired unit closings.