Ameren unveils new hybrid energy center combining natural gas and energy storage to supply reliable energy when Missouri needs it most

Site will create jobs, power thousands of homes

ST. LOUIS, June 27, 2025 /PRNewswire/ -- Ameren Missouri, a subsidiary of Ameren Corporation (NYSE: AEE), is taking the next step in its generation investment plan to enhance energy reliability for customers by filing an application with the Missouri Public Service Commission that includes a first-of-its-kind project for the company. The application involves the construction of an 800-megawatt (MW) simple-cycle natural gas energy center complemented by Ameren Missouri's first large-scale battery storage facility at one location in Jefferson County, Missouri. The Big Hollow Energy Center is designed to efficiently meet increased energy demands while ensuring grid resiliency.

"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."

The Big Hollow Energy Center will provide significant investment and jobs to the community. With timely regulatory approval, the energy center will be ready to serve as a reliable backup source of energy for customers in 2028. Similar in design to the Castle Bluff Energy Center, the natural gas portion of Big Hollow will be designed to deliver energy on the coldest winter days, hottest summer afternoons and back up the grid when renewable energy generation is otherwise unavailable.

Co-located on the site will be Ameren Missouri's first large-scale lithium-ion battery installation. 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 an acceleration of battery storage capacity, with a total of 1,000 MW planned by 2030 and a total of 1,800 MW by 2042.

The natural gas generation and battery storage facilities will operate independently while taking advantage of existing energy infrastructure on land Ameren Missouri already owns, reducing construction time and cost to customers.

"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."

The identified site, which Ameren Missouri already owns, has existing infrastructure and transmission line access, reducing overall construction time.

"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.

Community leaders welcome the announcement as well:

"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 Jefferson R-VII Board of Education and I deeply appreciate Ameren Missouri's communication regarding the closure of the Rush Island Energy Center. The company has addressed every concern about its closure and the impact on our students, consistently treating the district with the utmost respect," said David Haug, Ed.D., superintendent of the Jefferson R-VII School District. "With the Rush Island Energy Center's closure in October 2024, our primary goal was to retain Ameren as a community partner. We are pleased to continue this partnership with the announcement of the Big Hollow project."

About Ameren Missouri
Ameren Missouri has been providing electric and gas service for more than 100 years. Ameren Missouri's mission is to power the quality of life for its approximately 1.3 million electric and 135,000 natural gas customers in central and eastern Missouri. The company's service area covers approximately 60 counties and more than 500 communities, including the greater St. Louis area. For more information, visit Ameren.com/Missouri or follow us at @AmerenMissouri or Facebook.com/AmerenMissouri.

Forward-looking Statements
Statements in this release not based on historical facts are considered "forward-looking" and, accordingly, involve risks and uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there is no assurance that the expected results will be achieved. These statements include (without limitation) statements as to future expectations, beliefs, plans, projections, strategies, targets, estimates, objectives, events, conditions, and financial performance. In connection with the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause actual results to differ materially from those anticipated. The following factors, in addition to those discussed under Risk Factors in Ameren Missouri's Annual Report on Form 10-K for the year ended December 31, 2024, and elsewhere in this release and in our other filings with the Securities and Exchange Commission, could cause actual results to differ materially from management expectations suggested in such forward-looking statements:

• regulatory, judicial, or legislative actions, and any changes in regulatory policies and ratemaking determinations that may change regulatory recovery mechanisms;
• our ability to control costs and make substantial investments in our businesses, including our ability to recover costs and investments, and to earn our allowed returns on equity, within frameworks established by our regulators, while maintaining affordability of services for our customers;
• the effect on Ameren Missouri of any customer rate caps or limitations on increasing the electric service revenue requirement pursuant to Ameren Missouri's election to use the plant-in-service accounting regulatory mechanism;
• Ameren Missouri's ability to construct and/or acquire battery storage, as well as natural gas-fired energy centers, and implement new or existing customer energy-efficiency programs, including any such construction, acquisition, retirement, or implementation in connection with its Smart Energy Plan, preferred resource plan, or emissions reduction goals, and to recover its cost of investment, a related return, and, in the case of customer energy-efficiency programs, any lost electric revenues in a timely manner, each of which is affected by the ability to obtain all necessary regulatory and project approvals, including certificates of convenience and necessity from the MoPSC or any other required approvals;
• the cost of battery storage technologies and our ability to obtain timely interconnection agreements with the MISO or other regional transmission organizations at an acceptable cost for each facility;
• the inability of our counterparties to meet their obligations with respect to contracts, credit agreements, and financial instruments, including as they relate to the construction and acquisition of electric and natural gas utility infrastructure and the ability of counterparties to complete projects, which is dependent upon the availability of necessary materials and equipment, including those obligations that are affected by supply chain disruptions;
• advancements in energy technologies, including carbon capture, utilization, and sequestration, hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery energy storage, and the impact of federal and state energy and economic policies with respect to those technologies;
• the effects of changes in federal, state, or local laws and other domestic or international governmental actions, including monetary, fiscal, foreign trade, and energy policies, foreign trade tariffs, executive orders, or extended federal government shutdowns or defunding;
• the effects of changes in federal, state, or local tax laws or rates; additional regulations, interpretations, amendments, or technical corrections to, or in connection with the Inflation Reduction Act of 2022 ("IRA"), including the effects of the IRA as it relates to income tax payments or the transferability of production and investment tax credits and the 15% minimum tax on adjusted financial statement income; and challenges to the tax positions taken by us, if any, as well as resulting effects on customer rates and the recoverability of the minimum tax imposed under the IRA;
• the effects on energy prices and demand for our services resulting from customer growth patterns or usage, including demand from data centers, technological advances, including advances in customer energy efficiency, electric vehicles, electrification of various industries, energy storage, and private generation sources, which generate electricity at the site of consumption and are becoming increasingly cost-competitive;
• disruptions in the delivery of fuel, failure of our fuel suppliers to provide adequate quantities or quality of fuel, or lack of adequate inventories of fuel;
• the effectiveness of our risk management strategies and our use of financial and derivative instruments;
• the impact of cyberattacks and data security risks on us, our suppliers, or other entities on the grid, which could, among other things, result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the loss of data, such as customer, employee, financial, and operating system information;
• acts of sabotage, which have increased in frequency and severity within the utility industry, war, terrorism, or other intentionally disruptive acts;
• business, economic, geopolitical, and capital market conditions, including foreign trade tariffs or trade wars, evolving federal regulatory priorities, and the impact of such conditions on interest rates, inflation, and investments;
• the impact of inflation or a recession on our customers and suppliers and the related impact on our results of operations, financial position, and liquidity;
• disruptions of the capital and credit markets, deterioration in our credit metrics, or other events that may have an adverse effect on the cost or availability of capital, including short-term credit and liquidity, and our ability to access the capital and credit markets on reasonable terms when needed;
• the actions of credit rating agencies and the effects of such actions;
• the impact of weather conditions and other natural conditions on us, including the impact of system outages;
• the construction, installation, performance, and cost recovery of generation, transmission, and distribution assets;
• the effects of failures of natural gas storage facilities systems and equipment, which could result in unanticipated liabilities or unplanned outages;
• the impact of current environmental laws or their interpretation and new, more stringent, or changing requirements and environmental policies, including those related to New Source Review provisions of the Clean Air Act, carbon dioxide, nitrogen oxides, sulfur dioxide, and other emissions and discharges, cooling water intake structures, coal combustion residuals, energy efficiency, and wildlife protection, that could limit, terminate or otherwise modify the operation of certain of Ameren Missouri's energy centers, increase our operating costs or investment requirements, result in an impairment of our assets, cause us to sell our assets, reduce our customers' demand for electricity or natural gas, or otherwise have a negative financial effect;
• labor disputes, work force reductions, our ability to attract and retain professional and skilled-craft employees, changes in future wage and employee benefits costs, including those resulting from changes in discount rates, mortality tables, returns on benefit plan assets, and other assumptions;
• the impact of negative opinions of us or our utility services that our customers, investors, legislators, regulators, creditors, rating agencies, or other stakeholders may have or develop, which could result from a variety of factors, including failures in system reliability, failure to implement our investment plans or to protect sensitive customer information, increases in rates, negative media coverage, or concerns about company policies or practices;
• the impact of adopting new accounting and reporting guidance;
• the effects of strategic initiatives, including mergers, acquisitions, and divestitures;
• legal and administrative proceedings;
• pandemics or other significant global health events, and their impacts on our results of operations, financial position, and liquidity;
• the impacts of the Russian invasion of Ukraine and conflicts in the Middle East, related sanctions imposed by the United States and other governments, and any broadening of these or other global conflicts, including potential impacts on the cost and availability of fuel, natural gas, enriched uranium, and other commodities, materials, and services; and
• the inability of our counterparties to perform their obligations, disruptions in the capital and credit markets, prolonged government shutdowns or defunding, acts of sabotage or terrorism, including cyberattacks and physical attacks, and other impacts on business, economic, and geopolitical conditions, including inflation, foreign trade tariffs, trade wars, or recession.

New factors emerge from time to time, and it is not possible for management to predict all of such factors, nor can it assess the impact of each such factor on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement. Given these uncertainties, undue reliance should not be placed on these forward-looking statements. Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.

SOURCE Ameren Missouri