Very few clean technologies managed to scrape significant wins in the “One Big Beautiful Bill.” As compared with the Inflation Reduction Act, the bill phases out major incentives for solar and wind much sooner. But one of the rare winners post-reconciliation is linear generators — fuel-agnostic devices that turn mechanical motion directly into electricity.
Under the IRA, linear generators were eligible for the 30% tech neutral investment tax credit, but only through this year. But the OBBB essentially granted linear generators a massive extension, allowing projects to qualify for the credit if they start construction by the end of 2033.
For Stanford spinout Mainspring, that credit expansion “changed things overnight,” the company’s CEO Shannon Miller told Latitude Media.
Mainspring had a “limited number” of safe harbor projects that were slated to come online this year, Miller explained, and those would be eligible for the credit almost regardless of what happened during reconciliation. But 2026 and beyond was less clear.
“Longer term it was going to be much harder, because especially for a small company you can’t safe harbor that much,” she said, adding that some conversations with potential customers who wouldn’t qualify for the credit under an IRA repeal had slowed in the face of the uncertainty. “If you’re not sure if the tax credit is going to be there, a 30% swing in the pricing can be pretty dramatic.”
But after OBBB was signed into law, those conversations picked back up with zeal, and Mainspring’s sales pipeline has extended much further out, into 2028.
“Having that certainty really helps with moving forward on those (longer-term) sales,” Miller added. And that longer lead time is critical for small companies, particularly in the energy space: “We have a lot of clarity now, and the time frame is really critical because energy projects do take time, and so having that longer period now allows us to really focus on executing and building, and that’s a great place to be.”
A pipeline boost
In the last few years, data center developers have been a key customer segment for Mainspring. Their generator, which can ramp up and down quickly and switch between fuel types using software alone, can serve as a power source to replace diesel generators. For those customers, the company positions itself not only as a lower-emissions alternative — its system can run on any fuel, from fossil fuels to biofuels to hydrogen — but as a workaround to capacity and transmission constraints that can hold up data center builds.
But with the extension of the ITC, Mainspring has seen a surge in interest from another market segment struggling with transmission constraints: consumer-owned utilities.
Municipal utilities and electric cooperatives have slightly longer timelines than other customers — the company is largely discussing utility projects that wouldn’t start building until 2027 or 2028 — so Mainspring “didn’t have enough safe harbor for them,” Miller explained.
In the AI load growth era, consumer-owned utilities are finding themselves in a somewhat vulnerable position, she added. Munis and coops historically haven’t had the financial capacity or scale to develop their own generation projects. Instead, they’ve relied on large, centralized resources like coal or natural gas, which are owned and operated by IPPs or investor-owned utilities.
That setup, though it can help keep costs lower, means they’re also heavily dependent on transmission lines to bring power from those centralized resources to their local distribution systems. But because munis and coops are smaller players in the overall grid system, they generally aren’t “first in line” for transmission access, Miller said. In other words, when there are transmission constraints, they’re more likely to experience shortages.
According to Miller, the certainty of the ITC brings the cost of a Mainspring generator into their range: “With a solution like ours, and the ITC, they can build these smaller, competitively-priced resources that are sited near their load, and they can kind of take power [generation] into their own hands.”
In one instance, a municipal utility is building a 36 megawatt generator project just outside a town where a new data center is planned. “They’re concerned about being short power, and so they wanted something close to the town so that they weren’t worried about transmission and distribution,” she said.
That particular project, which isn’t yet formally announced, will run on propane in the near term, she added, but the muni plans to eventually transition to hydrogen. One key selling point for Mainspring, Miller said, was that the muni was worried about outages longer than four hours, which is the duration of most batteries on the market today. They expect the generators to be running between 10% and 30% of the time to support the local grid as the new data center comes online.
A tax credit puzzle
Heading into the reconciliation process earlier this year, Mainspring’s government affairs team was keeping an eye on several moving pieces.
First was the hoped-for extension of the tech neutral ITC. But even with the rhetoric around the need for firm power sources and the energy demands of AI, “it was very unclear which technologies would get support,” Miller said. And that uncertainty persisted right up to the final days of the process.
The initial House proposed repealing the tech neutral ITC, which would have required linear generator projects seeking to qualify to be under construction within 60 days of the law’s enactment. The final Senate version, of course, was more generous, leaving Mainspring with a longer runway than it had even under the IRA.
Another key element was the 45V hydrogen credit. As Miller told Latitude Media in May, the fate of that credit could impact how quickly Mainspring will grow, because the company has many customers looking to run green hydrogen pilots with the generators. The House version of the bill would have ended the 45V credit at the end of 2025. But a tightly coordinated effort by the hydrogen industry paid off, and the final version extended that timeline out to the end of 2027.
And then there are the foreign entity of concern restrictions. Miller said her team is waiting for additional guidance as far as those constraints go, but that Mainspring had already been working to build up a domestic supply chain that isn’t reliant on China, in part to avoid tariff uncertainty. “I don’t think we’re going to be in a situation where that’s going to impact us,” she added.
