AEP advances major clean energy investments in Wyoming and Mainspring technology
American Electric Power is developing a $4 billion, 702-MW fuel cell project in Wyoming under a 20-year PPA with Google and has agreed to buy up to 1.6 GW of Mainspring Energy’s linear generators over eight years.
American Electric Power (AEP) is advancing two major clean energy investments to enhance grid reliability. The utility is developing a 702-MW fuel cell project in Wyoming and has agreed to buy up to 1.6 GW of Mainspring Energy’s linear generators over the next eight years.
AEP plans to spend about $4 billion on the 702-MW Bloom Energy fuel cell project in Wyoming. The project includes plans to integrate carbon capture technology to deliver reliable, near-zero-emissions power. Bloom’s fuel cells produce electricity without burning natural gas. AEP expects to start building the Wyoming fuel cell project this year and bring it online in 2028. Construction of the facility is planned to start in 2026, with the plant expected to be fully operational by the end of 2028.
The Wyoming project follows agreements between Google and Black Hills Corp., effective Sept. 30. Google will buy the plant’s output under a 20-year power purchase agreement from Cheyenne Fuel Cell LLC. Black Hills Corp. owns a utility serving the Cheyenne area. AEP owns and controls about 92% of Cheyenne Fuel Cell LLC, while funds advised by Basalt Infrastructure Partners own nearly 8%. The Wyoming project is under contract to Google.
AEP secures large-scale Mainspring linear generator supply
AEP agreed to buy up to 1.6 GW of Mainspring’s linear generators over eight years, starting with 190 MW next year. The agreement spans the next eight years, with an initial 190-MW delivery set for next year. AEP will be able to buy about 200 MW per year under the agreement, which could be worth up to $4 billion. Linear generating units are expected to be online within 12 months of delivery.
Mainspring’s linear generators come in standard 2.5-MW configurations and can use natural gas, biogas, and hydrogen as fuel sources. The generators offer flexibility, including potentially firming renewable energy. They convert fuel to electricity via a low-temperature, flameless reaction that produces close to zero nitrogen oxide emissions. The transaction is Mainspring’s largest purchase order to date and marks its shift into the investor-owned utility market beyond commercial, industrial, and data center markets.
| Feature | Detail |
|---|---|
| Total Agreement Capacity | Up to 1.6 GW |
| Agreement Duration | 8 years |
| Initial Delivery | 190 MW (next year) |
| Annual Purchase Option | About 200 MW per year |
| Unit Configuration | Standard 2.5-MW |
| Potential Total Value | Up to $4 billion |
Mainspring was founded in 2010 and is based in Menlo Park, California. The company recently closed a $242 million Series G funding round led by Valiant Peregrine. All existing company investors participated, alongside a new strategic backer. Mainspring has raised over $1 billion in total funding across all rounds. Its investors include AEP, NextEra Energy, Gates Frontiers Fund, and Khosla Ventures.
Context: AEP’s broader clean energy and grid strategy
Bill Fehrman, AEP chairman, president and chief executive officer, said the moves address rising power demand. "As power demand continues to grow, AEP is bringing together new technologies and strong partnerships to deliver reliable, innovative energy solutions quickly and at scale." AEP’s utilities serve about 5.6 million customers across 11 states.
The Wyoming plant alone is about seven times the size of AEP’s previous fuel cell deployment. In 2025, AEP’s Ohio utility signed contracts for about 98 MW of fuel cell service to supply two Central Ohio data centers operated by Amazon Web Services and Cologix. The nearly 900 MW of planned generation and purchased equipment announced this week equals less than 3% of the roughly 33,000 MW of owned and contracted generating capacity that AEP reports.
In July, AEP said it had secured about 13 GW of gas turbines for deployment through 2031. The company has been active in fuel cell procurement. In November 2024, an AEP subsidiary agreed to buy 100 MW of solid oxide fuel cells, with an option for 900 MW more. Bloom announced a supply agreement with AEP for up to 1 GW and an initial 100-MW order at that time. In January, an unregulated AEP subsidiary entered into an unconditional agreement to purchase 'a substantial portion of its option for solid oxide fuel cells' for about $2.65 billion. That subsidiary also signed a 20-year agreement with an unnamed 'high investment grade third party customer' for all of the facility’s output.
Tom Linebarger, Mainspring chairman and CEO, highlighted the grid benefits of the linear generators. "Having the ability to both react to the customers’ needs and the grid’s needs at the same time gives them incredible flexibility." Combined, the two announcements represent 892 MW of planned generation and purchased equipment. The potential to reach approximately 2.3 GW exists if AEP buys the full amount available under the Mainspring agreement.
AEP expects to begin construction of the Wyoming fuel cell project in 2026 and bring it online in 2028.
