ATLANTA (AP) — Georgia Power Co. says increased demand for electricity is coming fast, asking regulators Friday to let it secure more power generation ahead of schedule.

But environmentalists are questioning a plan that would mostly rely on natural gas to generate new electricity and could keep some coal-fired plants running past previously projected shutdown dates. They say the largest unit of Atlanta-based Southern Co. needs to do more to cut climate-altering carbon dioxide emissions produced from burning coal and gas.

Georgia Power said it wants to build or contract for at least 3,365 more megawatts of generating capacity. That’s three times the capacity of one of its new nuclear reactors at Plant Vogtle near Augusta and would be enough to power about 1.4 million homes.

“Many businesses coming to the state are bringing large electrical demands at both a record scale and velocity,” Georgia Power CEO Kim Greene said in a statement.

Based on U.S. Energy Information Administration statistics, the investment could run into the billions of dollars, although the company repeatedly declined to provide an estimate Friday. Georgia Power’s 2.7 million customers would not fully pay for it until after 2026 under the plan the company proposed Friday to the Georgia Public Service Commission.

Bills have increased steeply this year as the company has charged more to pay for expensive natural gas, the costs of the Vogtle nuclear plant and other investments. A typical Georgia Power residential customer now pays an average of about $157 a month, including taxes.

The five-member elected commission would have to approve the spending. Proceedings are likely to follow in which consumer and environmental advocates challenge some of Georgia Power’s proposals, including plans to build new combustion turbines near Newnan that could burn natural gas or oil. They’re also unhappy about the possibility that the company could keep burning coal longer than previously expected at some existing plants in Georgia and Alabama.

“Pushing for more oil and gas is completely at odds with Georgia Power’s parent company, Southern Co.'s goal of net zero greenhouse gas emissions by 2050,” Jennifer Whitfield, an attorney for the Southern Environmental Law Center, said in a statement. “Georgia can and should instead meet our energy needs and customer demands by expanding clean, affordable renewable options like solar power, battery storage, and energy savings programs.”

Georgia Power’s plan does include additional battery storage and energy savings, but the company says it needs to balance generation sources.

Georgia Power typically discusses how to meet future demand once every three years. Commissioners approved the company’s last resource and rate plans in 2022, with the next one not scheduled until 2025.

But the utility now says it did not foresee a big spike in electricity demand associated with new development in Georgia. The utility projects increased demand is coming so quickly that it can’t wait until 2026 to start increasing supply and does not have time to seek more power from outside providers.

It said Friday that since the beginning of 2022, large new users that project they will require nearly 4,000 megawatts of electricity have contracted with Georgia Power for their future needs. That compares to about 100 megawatts of yearly large-user growth between 2017 and 2020.

Georgia Power says it has already signed a deal to buy 750 megawatts of power from a natural gas plant owned by Mississippi Power Co., a Southern Co. sister company. Mississippi Power has faced too much capacity and depressed financial results after a failed attempt to build a plant that would gasify and burn lignite coal, capturing carbon dioxide to pump underground.

Georgia Power also wants to buy 215 megawatts from a natural gas plant in Pace, Florida, that’s owned by LS Power, which wholesales electricity to utilities.

Georgia Power does plan some renewable power, seeking to build batteries to store 1,000 megawatts of solar power, including some at military bases. The company also says it will expand a program to link backup generators on customer property to the grid and programs to reduce demand, including doubling the growth of residential customers whose thermostats can automatically curtail heating and air conditioning when electricity demand is high.