Sav Morn News: Expert predicts Souco's proposed Plant McIntosh gas burner to be "costliest" in US

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ENERGY-RESOURCE

Georgia Power's planned Plant McIntosh gas could be among 'costliest' in U.S., expert says

Jillian Magtoto

Savannah Morning News

Updated Dec. 19, 2025, 10:28 a.m. ET

• Georgia Power proposes adding a new natural gas unit to Plant McIntosh as part of a major grid expansion.
• An expert witness testified the proposed unit would be the most expensive natural gas plant in the United States.
• Environmental groups and energy organizations fear the high costs will burden residential ratepayers for decades.

 

About 15 miles north of Savannah and right above the Savannah National Wildlife Refuge in Rincon, Ga., stands Plant McIntosh, a robust 10-unit gas plant made up of eight 80-MW combustion turbine units, and two 660-MW combined cycle (CC) units. In 2022, it was listed as the state's fourth-largest carbon dioxide emitter.

Under Georgia Power's proposed nearly 10,000 megawatt (MW) grid expansion, it could be getting an eleventh unit, an addition that has received much scrutiny in the past week.

In last week's final round of Georgia's Public Service Commission (PSC) hearings on Georgia Power's energy expansion, Sierra Club attorney Isabella Ariza called its expert witness to the stand.

In an assessment of Georgia Power's Request for Proposal, Synapse Energy Economics Senior Associate Lucy Metz submitted a piece of testimony that Plant McIntosh would be the most expensive natural gas plant built in the United States.

 

The new 747-MW unit “is the highest cost I have seen for a CC [combined cycle] plant in the United States," according to Metz's testimony.

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The former coal plant, retired in 2019, is named among three methane plants in Georgia Power's All-Source Resource Capacity request. The newest CC addition, McIntosh Unit 12, would produce 11% of Georgia Power's planned expansion.

As Georgia Power revs up to build new-generation capacity, largely to serve rapidly growing data center demand, they have filled most of their energy generation portfolio with CCs.

 

But environmental and energy organizations fear the plants will burden the average residential ratepayer. And the interveners representing them in the PSC hearings argue that CC costs will outlive the lifespan of data center contracts, pointing to Plant McIntosh for its high costs and the long-term financial risks it could pose.

"That is the one that sticks out like a sore thumb," said Southern Environmental Law Center (SELC) Attorney Jennifer Whitfield. "It is the most expensive option on the table, and we just don't need it."

More: If expansion gets approved, Georgia Power agrees to save residents $8.50 a month in 2028

Combined cycle, combined costs

CC facilities use two different kinds of thermodynamic cycles to generate electricity and therefore tend to have higher upfront costs than typical single-turbine gas plants. The most common CC plant is a combined cycle gas turbine (CCGT), using gas and steam turbines.

The argument for CCGTs is that their higher fuel efficiency will balance out over time and high enough loads, ultimately providing cheaper electricity and lower emissions.

But CCGT plant operations costs have been on the rise. According to a report by the American Public Power Association, CCGT projects cost about $2,000 per kilowatt, nearly double of what was originally projected for the next two years.

 

“The capital costs of combined cycle units have more than doubled since Georgia Power completed its 2025 IRP,” said Metz. “Building the proposed combined cycle units now will lock Georgia ratepayers into the current high costs for these resources for decades to come."

In the early 2000s, national CCGT capacity boomed to nearly 50 GW. But due to oversupply, market saturation and rising natural gas prices, new CCGT capacity steadily decreased. About half of today's CCGT capacity was built between 2000 and 2006, according to the U.S. Energy Information Association (EIA).

"Hardly any new natural gas capacity came online last year," reported the EIA—just one industrial CCGT power generator blipped online in the U.S. in 2024.

But as Georgia Power plans to contribute five more at plants Bowen, Wansley and McIntosh, it's not alone. Developers plan to add 18.7 GW of CC capacity in the U.S. by 2028, with 4.3 GW already under construction.

 

"However, developers of all those planned units are working through regulatory approvals and securing needed equipment, both of which add uncertainty to their construction costs and initial operation date," the EIA stated.

Rather than eliminating the option due to potential risk, the PSC states Plant McIntosh on the bottom of the utility's to-do list.

“We recognize its economics are not as good as the other ones, so that’s why you would put it towards the bottom” of the list, said PSC Utility Finance Director Tom Newsome. It would "be one of the last ones you pull."

 

Hinting what's ahead

As an intervener, SELC was privy to the projected cost breakdown of Georgia Power's energy portfolio, but "we can't share the actual cost publicly, unfortunately," said Whitfield.

And the fear is how these costs will outlast the contracts between Georgia Power its large-load customers.

 

"Because data center load is happening so rapidly and it's such a high magnitude that Georgia Power is having to procure much more expensive resources to serve that load," said Metz. "There's a very real risk that the data center load will instead drive up rates for existing rate payers unless we have these safeguards put in place."

The design lifetime of CCGT units is typically 25 to 30 years, according to the EIA. Georgia Power set an asset life of 45 years for each of the CCGT plants.

"So in 2070 we could still be paying for Plant Mcintosh, and won't need it," said said Whitfield.

According to Georgia Power’s rebuttal testimony, Metz’s analysis did not account for inflation.

 

“The appropriate adjustment for inflation demonstrates that the Company’s thermal resources are, in fact, comparable to other reported costs,” said the rebuttal testimony filed on Nov. 26.

But at the hearing, Metz did not budge.

"f you assume that inflation over the next 5 years will be somewhere between 2 and 2.5%, Mcintosh still falls at the very upper range or above the benchmark cost that I provide in my testimony," said Metz.

These benchmark costs provided a point of comparison among other regional utilities in the country, and did not prove that Georgia Power did "a bad job curating CC's. It's to point out how elevated CC costs are across the board for all utilities," said Metz.

Instead, Metz advises that Georgia Power should its near-term needs on battery storage with shorter lifetimes and therefore, lower risk.

"A combined cycle unit that comes online in 2030 will lock in capital and fuel costs through 2075, two to three times longer than the maximum length of a data center contract," said Metz. "In contrast, the 20-year lifetime of battery storage resources aligns more closely with typical data center contract length."

 

Jillian Magtoto covers climate change and the environment in coastal Georgia. You can reach her at jmag...@usatodayco.com.

This reporting content is supported by a partnership with Green South Foundation, Prentice Foundation and Journalism Funding Partners

 

 

 

 

 

 

 

 

 

 

 

 

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