Ameren Missouri Secures Approval to Develop Hybrid Energy Facility, Big Hollow Energy Center

Ameren Missouri, a subsidiary of Ameren Corporation, has received approval from the Missouri Public Service Commission to proceed with the Big Hollow Energy Center, a new hybrid energy facility designed to strengthen energy reliability for all customers across Missouri, including residential, small business and industrial customers.

The approval authorizes construction of an 800 MW simple-cycle natural gas energy center paired with a large-scale battery storage facility at a single site in Jefferson County, Missouri. The Big Hollow Energy Center will be integrated into Ameren Missouri's statewide generation and will support reliable electric service for customers throughout the company's service territory.

With regulatory approval granted, the Center is expected to be operational by 2028. Like the Castle Bluff Energy Center, the natural gas portion of Big Hollow will be designed to deliver energy during the winter days, summer afternoons and other periods of peak demand, while also supporting the grid when renewable energy generation is unavailable.

Ameren Missouri's large-scale lithium-ion battery installation will be co-located at the site. The planned 400-MW battery storage facility will be a fast-acting resource capable of responding within moments to support customers' energy needs.

Fully charged, the batteries are anticipated to power many homes for hours and help strengthen overall grid reliability, particularly during times of peak energy demand. Ameren Missouri plans to add 1,000 MW of battery storage by 2030 and a total of 1,800 MW across multiple sites by 2042.

The natural gas generation and battery storage facilities will operate independently while leveraging existing energy infrastructure Ameren Missouri owns, reducing construction time and cost to customers.

"Big Hollow adds flexibility and resilience to the energy system that serves customers across Missouri," said Ajay Arora, senior vice president and chief development officer at Ameren Missouri. "By combining fast-starting natural gas generation with battery storage, the project helps ensure reliable service for homes and businesses during periods of peak demand and changing system conditions."