ATLANTA — Starting May 27, Georgia Power executives will defend the mix of energy resources the utility intends to rely on for generating electricity against critics who say the plan relies too much on fossil fuels and not enough on renewable power.

The state Public Service Commission (PSC) will hold a second round of hearings expected to last several days on Georgia Power’s 2025 Integrated Resource Plan (IRP). The first round of hearings over three days in late March gave company witnesses a chance to outline how they propose to meet a massive increase in demand prompted by the growth of power-hungry data centers across the state.

The new IRP calls for Georgia Power to continue operating coal-burning plants at Plant Bowen near Cartersville and Plant Scherer near Macon, providing about 4,000 megawatts of electricity. A megawatt is enough electricity to power about 750 homes. The Atlanta-based utility also plans to upgrade existing natural gas units.

On the renewable side, the IRP proposes to add 4,000 megawatts of generating capacity from a combination of utility-scale and rooftop solar projects as well as battery storage.

But consumer watchdog and environmental advocacy groups argue Georgia Power could and should add more renewable energy to the utility’s portfolio beyond the 4,000 megawatts and do away with its aging fleet of carbon-emitting coal and gas plants.

“By arbitrarily capping solar development in its Integrated Resource Plan, Georgia Power has sidelined one of the most cost-effective resources available in favor of expensive fossil gas infrastructure,” said Patrick King II, Georgia policy advocate for the Natural Resources Defense Council. “This approach ignores more sensible pathways that would cut emissions, lower financial risk, and save bill payers money.”

But Georgia Power executives say the soaring demand for electricity to serve “large-load” customers including data centers makes retaining the coal and gas plants critical. The 2025 IRP estimates the utility will need an additional 8,200 megawatts of electrical generating capacity during the next six years, an increase of more than 2,200 megawatts above projections in an updated IRP the commission approved a year ago.

“We need these units,” Jeff Grubb, Georgia Power’s director of resource planning, testified during the hearings in March. “They’re an economical way to serve the load growth that we have.”

Grubb warned that if the company doesn’t keep those plants operating, it would need to build more expensive new generating capacity by 2032.

A key disagreement between Georgia Power and the IRP’s critics is over whether the utility really needs that much additional generating capacity.

During cross-examination of Grubb and other Georgia Power executives at the March hearing, energy lawyer Bobby Baker said the utility’s demand forecast has increased 27-fold since 2022.

“Doesn’t that raise some red flags for y’all, an enormous jump?” Baker asked the Georgia Power witness panel. “Hasn’t the company consistently overestimated load growth?”

Baker said the costs of overbuilding generating capacity would fall squarely on Georgia Power customers.

But Fernando Valle, director of forecasting and analytics for Georgia Power, defended the utility’s forecasting track record.

“The load forecast has always incorporated the best available information we have at the time of the forecast,” he said. “Predicting the future is inherently uncertain.”

Grubb said Georgia Power customers also would be on the hook if the company underestimates how much generating capacity will be needed.

“Under-forecasting is a bigger risk than over,” he said. “We don’t want to be short.”

The PSC is scheduled to vote on the proposed IRP on July 15.