Google signs first utility PPA for Kairos Hermes 2 reactor with TVA

TL;DR

• Google and the Tennessee Valley Authority (TVA) have signed a power purchase agreement to buy electricity from Kairos Power’s Hermes 2 reactor in Oak Ridge, Tennessee, marking the first such agreement for this advanced technology by a U.S. utility. The Verge
• Hermes 2 uses molten fluoride salt as a coolant and is planned to deliver about 50 MW of capacity, with Google set to receive clean energy attributes as part of the deal. The Verge
• The arrangement supports Google’s broader goal of adding up to 500 MW of new nuclear capacity by 2035, with Hermes 2 expected to supply the local grid serving Google’s Tennessee and Alabama data centers starting around 2030. The Verge
• The deal illustrates how clean energy attributes and power supply contracts can help developers deploy carbon-free power to the grid, while reflecting ongoing tensions and expectations around US nuclear innovation. The Verge

Context and background

Oak Ridge, Tennessee, has a deep history with nuclear development dating to the Manhattan Project era. Today it is the site of Kairos Power’s Hermes program, which aims to demonstrate a next-generation reactor using molten salt cooling rather than the traditional water-cooled approach. Kairos broke ground on its Hermes demonstration plant after receiving the Nuclear Regulatory Commission’s first construction permit in more than half a century for a non-water-cooled reactor. The Hermes 2 project, now under development, is positioned as one of the first reactors in a broader effort to revitalize a U.S. nuclear sector that some see as lagging behind other low- to zero-emission generation sources. The Verge Google has previously signaled interest in purchasing electricity from Kairos’ modular approach, with Hermes 2 described as the next step in Kairos’ demonstration program. The plan is clear: if Hermes 2 can deliver its stated capacity and reliability, it could help scale up nuclear output to meet rising electricity demand from major technology users and grid operators alike. The Verge In the broader context, the U.S. nuclear fleet consists of about 94 operating reactors with a combined capacity near 97,000 MW, contributing roughly one-fifth of the nation’s electricity mix in 2024. Hermes 2’s development reflects ongoing industry and policy interest in modern, potentially lower-cost nuclear options that could complement renewables and natural gas. The Verge

What’s new

The core development is the power purchase agreement between Google, TVA, and Kairos Power. TVA will buy electricity from Hermes 2 as it is developed near Oak Ridge and will subsequently provide clean energy attributes to Google, tying the company’s electricity use to carbon-free generation beyond what’s supplied by the existing grid. Hermes 2 is designed to deliver up to 50 MW of capacity, with construction and commissioning aiming toward grid delivery by around 2030. The agreement also fits into Google’s longer-term objective to help Kairos deploy up to 500 MW of new nuclear capacity in the United States by 2035. The Verge The announcement builds on earlier reports that Google would purchase electricity from multiple small modular reactors designed by Kairos Power. Hermes 2 is described as the next major milestone in Kairos’ program, following the Hermes demonstration reactor that began development last year after the NRC permit. This sequence underscores a push to bring more modern, high-temperature, low-pressure reactor designs into commercial operation. The Verge

Why it matters (impact for developers/enterprises)

For developers and large electricity users, acquiring carbon pollution-free power can be financially meaningful through two channels: sale of the electricity itself and the sale of clean energy attributes, which are certificates representing environmental benefits of avoiding fossil fuel emissions. Google will receive these clean energy attributes from Hermes 2 via TVA, supporting its climate and sustainability goals while potentially improving the economics of deploying carbon-free generation to meet corporate demand. While the benefits of these attributes can be debated in terms of environmental impact accounting, the arrangement demonstrates a pathway for integrating innovative nuclear projects into corporate decarbonization strategies. The Verge From a broader industry perspective, the deal could help accelerate the deployment of next-generation nuclear technologies that promise different cost and design contours compared with legacy reactors. If successful, Hermes 2 and similar projects could contribute additional carbon-free capacity to the grid and provide new options for meeting rising electricity demand from AI workloads and data centers, alongside renewables and gas-fired generation. The Verge

Technical details or Implementation

Kairos Power’s Hermes 2 relies on molten fluoride salt as a coolant, unlike conventional water-cooled reactors. This design choice offers a higher boiling point and the ability to operate at relatively low pressure, which in turn reduces the need for large, high-pressure containment structures and can lower upfront costs. Hermes 2 is part of Kairos’ broader Hermes program, which began with a demonstration reactor prior to Hermes 2 and has already received the NRC’s construction permit for a non-water-cooled reactor in more than fifty years. Oak Ridge, the reactor site, is deeply tied to the region’s nuclear history and is now a hub for new nuclear energy projects and research. The Verge The technical assessment suggests that low-pressure, molten-salt cooling could enable simpler containment and potential cost reductions, factors that are central to Kairos’ strategy for scaling up to hundreds of megawatts of new nuclear capacity. Hermes 2’s target capacity of 50 MW represents a stepping stone toward the broader goal of adding 500 MW by 2035. Google’s plan links the reactor’s output to its data-center operations in Tennessee and Alabama, with the local grid expected to benefit from the additional zero-emission power as the project progresses toward commercial operation. The Verge From a grid perspective, TVA’s involvement signals a shift in how utilities partner with private sector players to procure carbon-free power and associated environmental credits, a model that could influence future PPA activity around advanced nuclear and other low-emission technologies. The Verge

Key takeaways

• First PPA by a U.S. utility for this level of advanced nuclear technology connects Google’s data-center power needs with Kairos Power’s Hermes 2 project via TVA. The Verge
• Hermes 2 uses molten fluoride salt coolant and aims for relatively low-pressure operation, enabling potential cost reductions and simpler containment relative to traditional reactors. The Verge
• Google’s long-term target includes deploying up to 500 MW of new nuclear capacity by 2035, with Hermes 2 expected to deliver electricity to Google’s TN/AL data-center grid around 2030. The Verge
• The deal underscores how clean energy attributes can support corporate decarbonization while highlighting ongoing debates about the environmental impact of such certificates. The Verge

References

• The Verge