Dive Brief:
- Ameren on Monday filed a 20-year integrated resource plan with Missouri regulators that calls for dramatically increasing its reliance on natural gas generation from about 5% of its current resource mix to 60% by 2045 while zeroing out coal.
- The utility, which serves about 1.3 million customers across the central and eastern parts of the state, said it plans to add some 10.6 GW of new gas resources, 3.6 GW of new solar generation, 1.5 GW of wind, 2.4 GW of storage and 1.2 GW of new nuclear generation.
- Company executives said the plan was designed to ensure a diversity of resources to maintain reliability and manage costs. But environmental advocates were critical of Ameren’s plan, which they said would significantly increase its reliance on fossil fuels and could delay some coal plant retirements.
Dive Insight:
Ameren told regulators that it sees substantial load increases coming from data centers. It noted in its plan that Missouri state law and the company’s internal plans include provisions to ensure these large loads cover the costs of the infrastructure needed to serve them.
The utility said the addition of large loads will grow its base customer deliveries by 60% from 2027 to 2030. Over the course of the IRP, Ameren anticipates an annual sales growth rate of 5%-6%. The utility said it has committed to serving 2.8 GW of aggregate large-load demand by 2030, almost double the 1.5 GW included in its 2025 expectations. And that figure could grow substantially over the two decades the plan covers, Ameren said.
The utility’s current pipeline of prospective large load customers, including data centers, indicates “potential for considerable growth,” according to the IRP. The base case scenario forecast for large load deliveries represents approximately 1,400 GWh in 2027, increasing to 44,676 GWh by 2046, with a compound annual growth rate of 20%, the utility said.
To meet the demand, Ameren is planning for 2,100 MW of combined-cycle natural gas generation resources to be in service by 2031, another 2,800 MW by 2035 and 1,400 MW more by 2042. The utility also plans to build 1,900 MW of simple-cycle gas generation resources by 2029, with an additional 2,400 MW after 2040.
It also plans to add 500 MW of natural gas fuel cells by 2030. It will be “supplementing those on-demand generation resources” with 1,300 MW of new solar by 2030 and an additional 2,300 MW of solar by 2045. The plan also calls for 2,400 MW of battery storage by 2030 and 1,500 MW of wind energy resources after 2030. By 2040, another 1,200 MW will come from new nuclear.
“Although neither a location nor a technology has been selected yet, both advanced large-scale reactor designs and small modular reactors are being considered,” Ameren said. The utility also expects to seek an extension to operate the Callaway nuclear plant beyond 2044.
"This plan provides a clear path for maintaining reliability,” Ameren Corp. Chairman, President and CEO Martin Lyons Jr. said in a statement. The IRP makes the most of existing resources “while prudently investing in a mix of additional generation technologies.”
The plan includes the retirement of all of Ameren Missouri's coal-fired generating capacity, including Sioux Energy Center by the end of 2035 and all four Labadie Energy Center units by the end of 2042, it said.
"Because no single technology can meet every customer's energy needs on its own, the IRP evaluates how resources can work together to maintain reliability, adapt as customer energy use evolves, and manage costs over time,” Ameren Missouri Chairman and President Aaron Melda said in a statement.
Environmental advocates noted that the plan included options for extending the life of Ameren’s Labadie and Sioux coal plants. The Trump administration has moved to roll back greenhouse gas and other regulations on coal and gas-fired units, introducing uncertainty in resource planning.
“Given the lack of certainty regarding future regulatory programs, Ameren Missouri has necessarily made good faith assumptions based upon available information regarding potential future compliance measures,” the plan says, adding that such assumptions are subject to revision.
“The saying goes to stop digging if you’re in a hole, but Ameren is still digging with its pollution-heavy plan even though it admits extreme weather events are increasing,” Jenn DeRose, Sierra Club’s Beyond Coal campaign strategist in Missouri, said in a statement. “We need Ameren to stop making bad investments for families and small businesses, and this plan is full of them.”
Ameren files its IRP with the Missouri Public Service Commission every three years, though it may update it more frequently. The utility in June filed a $343 million rate increase with regulators, possibly raising residential monthly bills by about 10%, according to local news reports.
