Ameren Missouri plans to build a new natural gas power plant in south St. Louis County, on the site of a former coal plant.
The proposed Castle Bluff Energy Center would cost Ameren about $800 million.
The company would use the plant as a backup source of energy during peak demand, like extreme weather events, rather than as a base load that is always on. The project is a necessary element in Ameren’s transition toward renewable energy, said Jeff Moore, the company’s director of combustion turbine generators.
“Honestly, renewable energy and these backup plants like Castle Bluff, they really do go hand in hand,” Moore said.
Ameren plans to build at the former location of the Meramec Energy Center, a coal-fired power plant that closed at the end of 2022. A natural gas pipeline runs near the location. Moore said the existing connection to the transmission grid and other elements would make the project easier and cheaper to build.
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Proponents of renewable energy are questioning the company’s investment in natural gas. Jenn DeRose, senior field organizer for the Sierra Club’s Beyond Coal Campaign, said Ameren needs to be significantly more transparent in how it decided to move forward with this project.
“I'm especially curious if Ameren evaluated the variety of clean energy incentives that were offered in the Inflation Reduction Act,” DeRose said. “Now there's tons of money available to find cleaner, safer, and more affordable ways to meet energy demand.”
James Owen, executive director of Renew Missouri, said there are cheaper options that are also better for the environment. He questions how the plan aligns with Ameren’s goal to have net-zero carbon emissions by 2045.
“This is still taking fossil fuels and burning them into the air,” Owen said. “When you've got options such as wind, solar, battery storage, energy efficiency, which I will give credit to Ameren, they have invested a lot of money into all of those things. But to say that this is somehow some sort of more viable option, I just don't believe that's the case.”
Burning natural gas as an energy source leads to less greenhouse gases than coal but still leads to methane emissions. Methane has a shorter life in the atmosphere but is more than 28 times as potent at trapping heat as carbon dioxide. Ameren spokesperson Brad Brown said of the Castle Bluff proposal, “there are virtually no expected methane emissions coming from the exhaust stacks and the site will be designed to minimize any potential leakage.”
Ameren has multiple projects coming on and off line this year. A court decision will force Ameren to close the Rush Island Coal Plant before October. The company also is planning to launch the largest solar project in the state in northeast Missouri later this year. Missouri’s Public Service Commission approved the project earlier this month.
Ameren will still need to formally submit the proposal to Missouri’s Public Service Commission and go through its regulatory steps before the project is approved. The utility aims to start construction in the summer of 2025 and expects the plant could begin to provide energy to customers in 2027.
