Duke Energy unveils plans for new natural gas plant in Catawba County

Duke Energy has unveiled its plans for a new natural gas plant in Catawba County, part of the utility’s transition away from coal that nonetheless shows its continued reliance on other fossil fuels.

Duke filed an application to construct a new plant with the N.C. Utilities Commission late last week. It would contain two units, for a total capacity of 850 megawatts, to replace the existing Marshall Steam Station. One of Duke’s largest plants in the Carolinas, Marshall currently burns both coal and natural gas. 

The new plant would “allow for the orderly, planned retirement of coal capacity, while increasing flexibility of the system,” Duke officials said in the company’s filings with the Utilities Commission.

If the commission approves Duke’s application, construction is scheduled to begin in the third quarter of 2026, with completion by early 2029. The plant is expected to operate for 35 years and could incorporate hydrogen power, should that technology mature.

The application piggybacks on Duke’s revamped energy forecast, issued Jan 31. In that document, Duke cited “unprecedented” energy demand as a reason for its natural gas projects. In addition to the new Marshall natural gas plant, Duke plans to build another plant in Person County, which will connect to a proposed pipeline to be operated by Dominion Energy.

While Duke’s new natural gas plants would reduce carbon dioxide emissions as legally required, they would still emit significant amounts of methane, a potent greenhouse gas and driver of climate change. (Marshall would still use ultra-low sulfur diesel, also a greenhouse gas, as a backup fuel.)

Twenty years ago, natural gas accounted for just 2% of North Carolina’s greenhouse gas emissions; now that figure is 44.6%, according to the state’s new Greenhouse Gas Inventory, released in late January.

Climate change is altering temperatures and weather patterns worldwide, with catastrophic consequences: stronger hurricanes and tornadoes, wildfires, droughts, floods and heat waves. The year 2023 was the warmest since global records began in 1850, according to NOAA. The 10 warmest years since then have all occurred in the last decade.

To address the existential threat of climate change, the Utilities Commission has required Duke to pursue a “least-cost” path to reducing carbon dioxide emissions by 70% over the next decade. Duke also must achieve net-zero carbon emissions by 2050, unless the Utilities Commission grants an extension.

Cost details of building the new Marshall plant are not yet publicly known. Utilities Commission filings with those figures are not public because they contain commercially sensitive information.

However overall, construction of the new natural gas plants, plus three small modular nuclear reactors planned for Stokes County, would spike customers’ average monthly energy bills, according to the utility’s own estimates. By 2033, Duke Energy Progress customers would pay 39% more over previous estimates; Duke Energy Carolinas would pay 73% more per month.

Will Scott, Southeast Climate and Clean Energy director at Environmental Defense Fund, criticized Duke’s plans to build the new Marshall plant.

“It’s unfortunate to see this unnecessary, polluting gas plant proposed when Duke Energy’s own plans show that this kind of unit can be replaced economically with clean alternatives like solar and batteries,” Scott said. “At a time when $1 billion of unanticipated gas costs from last year are pushing bills skyward, it’s the wrong choice to put customers on the hook for even more of this dirty, price-volatile fuel for decades to come.”

While methane lingers in the atmosphere for less time than carbon dioxide, it traps more heat per molecule, and does more damage even in its shorter lifespan.

The EPA estimates natural gas pipelines leak about 367,000 tons of methane each year; however, an Environmental Defense Fund analysis puts that figure at 1.3 million to 2.8 million tons, annually. To extract more precise data, on March 4, EDF launched MethaneSAT, a satellite to help measure methane emissions from oil and gas facilities worldwide. The data collected by the satellite will be public.

The new Marshall natural gas plant would not require a new transmission pipeline, Duke officials said in the application. Instead, the plant would rely on an existing pipeline operated by Piedmont Natural Gas, a subsidiary of Duke. 

However, Piedmont would expand its interconnection with the Transco pipeline, which runs from the Gulf Coast through North Carolina, and to the Northeast. And Transco just announced it would expand in North Carolina, parallel to its existing pipeline. (Transco is holding a virtual informational meeting tonight; register here.)

Duke does plan to incorporate 17,500 megawatts of solar energy within 15 years. Additional battery storage paired with solar could boost the resource’s availability at night.

And the utility still plans to build an offshore wind farm off the Brunswick County coast, even after selling the company’s commercial renewable energy arm last year. However, the first pulse of energy won’t arrive until 2033 or 2034, about two years later than originally planned. Duke had not factored onshore wind into the mix, but now plans to build a farm — somewhere — to be in service by 2033. The two wind power sources are projected to make up a total of 2% of the energy mix in 2033, increasing to 12% by mid-century.

Still, those renewable energy projects are dwarfed by the enormous and interconnected natural gas infrastructure undertaken by several utilities: power plants, liquified natural gas storage facilities, pipelines and compressor stations.

“Duke’s actions suggest that they are mostly interested in building expensive methane gas infrastructure, as quickly as possible,” said Mikaela Curry, the Sierra Club’s field manager for several southeastern states, “while dragging their feet on clean, renewable energy.”