American Electric Power has agreed to buy up to 1.6 GW of linear generators from Mainspring Energy through 2034, the Menlo Park, California-based manufacturer announced on Oct. 13, 2026. Under the agreement, AEP purchased a first tranche of 190 MW, with delivery beginning in 2027, according to Mainspring. The company said the units will support rising power demand from AI data centers, manufacturing and electrification, and called the agreement "the largest procurement of linear generators to date."

For Mainspring, the deal marks a move into a new customer class. The company said the agreement extends its business beyond the commercial, industrial and data center markets "into the investor-owned electric utility sector at gigawatt scale." Mainspring said it began commercial shipments of its generators in 2020.

The terms disclosed

Beyond the first 190-MW tranche, AEP may buy additional units up to the 1.6-GW total over the next eight years. In an interview with Bloomberg Tech on Oct. 13, Mainspring Chairman and CEO Tom Linebarger said the agreement could be worth up to $4 billion and that AEP will be able to buy about 200 MW a year, Utility Dive reported on Oct. 15. Linebarger also said the units are expected to be online within 12 months.

Both chief executives framed the deal around how quickly capacity can be added. "Mainspring's linear generators can provide additional capacity quickly and efficiently, allowing us to better support growing energy needs," AEP Chairman, President and CEO Bill Fehrman said in Mainspring's announcement. In the same release, Linebarger said, "American Electric Power is demonstrating strategic leadership in navigating speed-to-power requirements."

In the Bloomberg Tech interview, Linebarger said the dispatchable units, which can run on different fuels, give AEP flexibility, including by potentially firming renewable energy. "Having the ability to both react to the customers' needs and the grid's needs at the same time gives them incredible flexibility," he said, according to Utility Dive.

How a linear generator works

Mainspring's product page says the generator compresses air and fuel until "a uniform, non-combustion reaction occurs" that "pushes oscillators through copper coils 13 times per second to generate electricity," POWER reported. Utility Dive described it as a low-temperature, flameless reaction that produces close to zero nitrogen oxide emissions, according to the company.

POWER drew the following specifications from a recent Mainspring datasheet:

  • Package size: 2.5-MW packages made up of ten 0.25-MW units. At that rating, the 190-MW first tranche is equivalent to 76 packages, by POWER's calculation.
  • Fuels: any blend of biogas, natural gas, hydrogen and propane.
  • Efficiency: 46% electrical efficiency on a lower-heating-value (LHV) basis, and a heat rate of 8,233 Btu/kWh on a higher-heating-value (HHV) basis.
  • Emissions: nitrogen oxide emissions below 1.5 ppm.

The companies

The two companies already had a working relationship. They signed a memorandum of understanding in 2022 to pilot the technology in Oklahoma, according to POWER. Utility Dive reported that Mainspring, founded in 2010, recently closed a $242 million Series G round led by private equity firm Valiant Peregrine and has raised a little more than $1 billion in total, according to a company spokeswoman. Its investors include AEP, NextEra Energy, Gates Frontiers Fund and Khosla Ventures, Utility Dive reported.

The agreement lands as AEP lines up generation for a growing pipeline of large loads. AEP reported 69 GW of contracted load additions through 2030 during its second-quarter earnings call, up 6 GW from the previous quarter, with Texas accounting for 45 GW and Ohio for 12 GW, according to POWER. The company said it had secured about 13 GW of gas-fired turbine capacity. In a separate announcement on Oct. 14, AEP said it plans to spend about $4 billion on a 702-MW Bloom Energy fuel cell plant in Wyoming to supply Google. AEP's current capital plan totals $78 billion for 2026 through 2030, POWER reported.

What Happens Next

AEP is scheduled to report third-quarter results and introduce its 2027–2031 capital plan on Oct. 28, 2026, according to POWER. Delivery of the first Mainspring units is set to begin in 2027. Neither company has identified where the first units will be installed or which customers they will serve.

Sources