Regulators approve new Ameren Missouri data center rate structure

The Missouri Public Service Commission has approved a new rate structure for large-load users, including Ameren Missouri, that includes financial and contractual commitments to help ensure data centers and other large power demand users pay their share of grid infrastructure and energy costs.

"Our plan is built on a simple principle: Missouri is an attractive state for economic development, and all customers deserve reliable service as well as just and reasonable rates," Michael Moehn, interim chairman and president of Ameren Missouri, said in a Nov. 24 statement. Ameren Missouri's legal name is Union Electric Co.

The approved Ameren Missouri plan includes "strict consumer protection" measures, in line with recently enacted Senate Bill 4, requiring new large-load businesses to pay 100% of direct interconnection costs up front and establishing financial security and collateral requirements that equal two years of minimum monthly bills, the company said in the statement.

Ameren Missouri, a subsidiary of Ameren Corp., expects "robust" data center demand. Its third-quarter earnings presentation indicated roughly 3 GW of signed construction agreements, up from about 2.3 GW as of Aug. 1.

Consumer protections in the rate structure include: no rate discounts or incentives for large-load customers; minimum monthly demand charges of 80% of the large-load customer's maximum requested power demand, even if they use less; required long-term contracts of 12 to 17 years, with automatic extension and early termination fees if minimum obligations are not met; and revenue sharing with other customer classes, including income-eligible customers, when Ameren Missouri's profits exceed authorized levels.

Power generation fuel mix outlook

"With our balanced energy mix, a robust and reliable transmission system and some of the lowest electric rates in the country, we're sending a clear message: Missouri is open for business," said Rob Dixon, senior director of economic, community and business development for Ameren Missouri.

The St. Louis-based utility's 2025 Preferred Resource Plan assumes power demand growth of 1 GW by the end of 2029 and 1.5 GW by the end of 2032.

Ameren Missouri's power generation fuel mix includes solar and wind power, hydropower, coal-fired power, landfill gas and nuclear power. The company has about 2.7 GW of incremental power generation projects in progress, according to its earnings presentation.

Ameren added about 700 MW of signed construction agreements with data center developers for projects within its Missouri service territory during the third quarter.

Developers of data center sites with construction agreements in place have so far made nonrefundable payments of $38 million to cover necessary transmission upgrades, "which demonstrates their confidence in and commitment to the proposed projects," Martin Lyons, Ameren's chairman, president and CEO, said during the third-quarter earnings call.

Ameren's service territory in downstate Illinois has attracted data center developers that are advancing projects with expected incremental power demand totaling 850 MW. Ameren Illinois Co. has signed construction agreements with these developers and received payments to support the necessary transmission interconnections, Lyons said.

More broadly, the utility has about 36 GW of economic opportunities in its development pipeline, split about evenly between Missouri and Illinois, the CEO added. He said about 80%-90% of those economic opportunities are for data centers and most of those are in the early stages of looking at various sites.

"We're accelerating investments in dispatchable energy generation, storage and electric infrastructure to ensure we can meet the needs of all of our customers at fair and reasonable rates," Ajay Arora, Ameren Missouri's senior vice president and chief development officer, said in a news release regarding the rate structure decision.