Missouri Utility Files for New 800-MW Gas Plant and First Large-Scale 400-MW Battery Energy Storage Facility
Key Insights
Ameren Missouri plans to build an 800-MW natural gas-fired power plant and a 400-MW battery energy storage facility near St. Louis, aiming for a 2028 operational date.
The project is part of Ameren's strategy to enhance grid reliability, meet increasing energy demand, and diversify its generation portfolio while phasing out coal-fired power plants.
The 400-MW lithium-ion battery system will be Ameren Missouri's first large-scale installation, supporting grid stability during peak demand and accelerating the utility's storage capacity goals to 1,800 MW by 2042.
The new facilities will operate independently, leveraging existing infrastructure to minimize costs and construction time, and are expected to bring economic benefits to Jefferson County.
Ameren Missouri, a subsidiary of Ameren Corp., has filed an application with state regulators to construct an 800-MW natural gas-fired power plant and its inaugural large-scale battery energy storage facility near St. Louis. The proposed Big Hollow Energy Center in Jefferson County, slated for operation by 2028, marks a pivotal step in the utility’s investment strategy aimed at enhancing energy reliability and diversifying its generation assets.
The Big Hollow facility, designed as a simple-cycle plant, mirrors the utility's planned 800-MW gas-fired Castle Bluff Energy Center, which will occupy the site of the former coal-fired Meramec Energy Center. This initiative underscores Ameren Missouri’s ongoing transition away from coal, following the closure of its Meramec plant in 2022 and Rush Island last year, with plans to retire the Sioux Energy Center by 2032. The utility continues to operate the 2,400-MW Labadie coal plant, Missouri's largest generation facility.
Mark Birk, chairman and president of Ameren Missouri, emphasized the strategic importance of these investments. "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," Birk stated, highlighting the utility's commitment to reliable energy while preparing for anticipated demand increases. Both Big Hollow and Castle Bluff are engineered to provide critical dispatchable power during periods of high energy demand, such as extreme weather conditions, thereby supporting grid stability when intermittent renewable sources are unavailable.
A key component of the Big Hollow project is Ameren Missouri's first large-scale lithium-ion battery installation, a 400-MW system. These batteries are designed to charge when excess energy is available on the grid and discharge rapidly to meet customer needs, capable of powering thousands of homes for hours. This aligns with Ameren Missouri's accelerated targets to deploy 1,000 MW of battery energy storage by 2030 and 1,800 MW by 2042.
Local officials have voiced support for the project. Dennis Gannon, Jefferson County executive, remarked, "The Big Hollow Energy Center represents more than just an energy project; it's a commitment to the future of Jefferson County." Ajay Arora, senior vice president and chief development officer at Ameren Missouri, underscored the importance of a balanced mix of generation technologies strategically located across the region to maximize energy output. The natural gas generation and battery storage facilities will operate independently, leveraging existing infrastructure on Ameren-owned land to optimize construction timelines and costs. Rob Dixon, senior director of economic, community and business development, noted the project’s local benefits, including job creation and support for the Jefferson R-VII School District and first responders.