Georgia Power does not plan to build any additional power plants over the next several years, saying demand growth is slow enough to be covered by existing power stations, the Plant Vogtle nuclear expansion and energy efficiency.

The utility on Thursday also predicted “no significant impact” on customer bills in 2014 from costs related to closing coal and oil units, new environmental programs or efficiency efforts that cut demand.

Georgia Power filed its 20-year energy plan with state utility regulators. The report said customers will get the bulk of their power from natural gas.

Once a dominant fuel for electricity generation, coal’s use will continue to diminish as Georgia Power closes more than a dozen coal and oil-fired units. The utility will equip other coal units with pollution controls to comply with federal environmental rules.

As recently as a year ago, Georgia Power and its parent, Atlanta-based Southern Co., complained about new environmental regulations to reduce toxic emissions from power plants, saying those rules could force the utility to close several coal plants and threaten peak capacity. Company officials said that is no longer a concern because long-term demand is not as high as they once predicted.

Also, the utility can use other technology to clean up coal units that will be cheaper than closing them or using pollution controls.

Two new reactors being built at Plant Vogtle, near Augusta, will be Georgia Power’s only new major source of electricity. The utility will buy some solar power from independent sources. It also is considering options to buy wind energy from states such as Oklahoma, company executives said.

Georgia Power gets 47 percent of its fuel from natural gas; 35 percent from coal; 18 percent from nuclear; and a small amount from hydropower and other renewable sources. The utility did not have figures on how that mix will change.

Environmental and consumer groups have pushed Georgia Power to add renewables and to shut down more coal and oil units than the 15 planned.

The Public Service Commission must review and approve the plan, updated every three years. The company uses factors including the state’s population, housing, industrial production, employment and weather, to determine electricity needs and whether there are enough power plants to provide that.

“We’re going to have sufficient capacity,” said Kyle Leach, Georgia Power’s resource policy and planning director. “Coming out of this great recession, we’ve continued to see kind of the rebound … kind of that delay in recovery.”

Running power plants more efficiently and encouraging customers to save energy are other ways to reduce demand.

“(Energy efficiency) is kind of our first resource,” said Greg Roberts, Georgia Power’s vice president of pricing and planning.

As a regulated monopoly, Georgia Power must provide electricity to all customers in its territory. It is allowed to recoup the costs of providing that power plus a profit. Customer bills rose after a rate increase approved in 2010, and Georgia Power can petition the PSC to change rates again starting in 2013.

“We’re still studying our options,” company spokesman Mark Williams said.