Missouri Utility Plans New 800-MW Gas-Fired Plant, Will Include Energy Storage

A utility that serves customers in Missouri announced it plans to build an 800-MW natural gas-fired power plant, along with the company’s first large-scale battery energy storage facility, at a site near St. Louis.

Ameren Missouri, a subsidiary of Ameren Corp., in late June filed an application with state regulators for the project. The utility said the Big Hollow Energy Center in Jefferson County is part of the company’s investment plan to improve energy reliability for customers and add more power generation to its portfolio.

Big Hollow, expected to come online in 2028 if approved by regulators, will be a simple-cycle plant, similar in design to the utility’s planned 800-MW gas-fired Castle Bluff Energy Center near St. Louis. Castle Bluff will be located on the site of the former coal-fired Meramec Energy Center, situated near the confluence of the Meramec and Mississippi rivers. The Meramec coal plant closed in 2022.

Ameren Missouri is phasing out coal-fired power generation. The utility closed its Rush Island coal plant last year, and plans to retire its Sioux Energy Center by 2032. The utility still operates the 2,400-MW Labadie coal plant, the state’s largest power generation facility.

‘Invest in Energy Infrastructure’

“This is the next step to deliver on our strategy to invest in energy infrastructure for our customers’ benefit and provide a balanced generation portfolio,” said Mark Birk, chairman and president of Ameren Missouri. “As we transition our generation for the future, we’ll continue to serve our customers with the reliable energy they expect while also preparing for anticipated increases in demand.”

Ameren in a news release said Big Hollow and Castle Bluff each are being designed to provide electricity when needed during periods of high energy demand, such as the coldest days of winter and the hottest days of summer, to support the grid when intermittent renewable energy is unavailable.

Big Hollow will feature Ameren Missouri’s first large-scale lithium-ion battery installation. The company said the batteries “can be charged at times when excess energy is on the grid and then utilized in any weather. The planned 400-MW battery storage is a fast-acting asset, ready in moments to support customers’ energy needs. Fully charged, the entire array could power thousands of homes for hours and help overall grid reliability, especially during times of peak energy needs.” Ameren Missouri recently announced it would accelerate the utililty’s battery energy storage capacity, with a total of 1,000 MW planned by 2030, and a total of 1,800 MW by 2042.

‘Commitment to the Future’

“The Big Hollow Energy Center represents more than just an energy project; it’s a commitment to the future of Jefferson County,” said Dennis Gannon, Jefferson County executive. “We’ve worked closely with Ameren Missouri over the past several years, and this forward-thinking investment will strengthen our local economy generations to come. We’re proud to partner with Ameren Missouri to help power progress in our community.”

The utility said the natural gas generation and battery storage facilities will operate independently. Each will utilize existing energy infrastructure on land Ameren Missouri already owns, reducing construction time and building costs.

“It is crucial to have a balanced mix of generation technologies and equally important to strategically locate them across the region,” said Ajay Arora, senior vice president and chief development officer at Ameren Missouri. “This approach maximizes the energy output from these resources.”

“We have collaborated with leaders across Jefferson County for years, and it’s exciting to locate the Big Hollow Energy Center and continue to invest in the community because it will bring jobs, support the Jefferson R-VII School District, first responders and others in the county,” said Rob Dixon, senior director of economic, community and business development at Ameren Missouri.

—Darrell Proctor is a senior editor for POWER.