Company officials said in a statement Monday they will request approval from the Georgia Public Service Commission to decertify and retire the 15 units.
The company said several factors, including economic conditions and the cost to comply with existing and future environmental regulations, contributed to the decision to close the units.
Units that would be decertified are in Putnam, Coweta, Glynn and Chatham counties.
Georgia Power said most of the units are coal-fired generating units. Two units at Plant McManus in Glynn County are oil-fired; and one unit at Plant Kraft in Chatham County is oil- or natural gas-fired.