TVA Inks First U.S. Utility PPA for Gen IV Nuclear Power in Landmark Three-Way Deal with Google, Kairos

The Tennessee Valley Authority (TVA) has signed a first-of-its-kind power purchase agreement (PPA) with advanced nuclear technology firm Kairos Power to buy power from the company’s planned Hermes 2, a molten salt nuclear reactor, in Oak Ridge, Tennessee. The deal makes TVA the first U.S. utility to contract for electricity from a Gen-IV reactor.

Under the agreement announced on Aug. 18, Kairos Power’s Hermes 2 plant—now designed as a single molten salt reactor uprated to 50 MWe from an earlier 28-MWe two-reactor configuration—is slated to begin operations in 2030. The project will supply 24/7 carbon-free electricity into TVA’s system to support Google’s rapidly growing data centers in Tennessee and Alabama.

“Here’s how it works: TVA will purchase electricity from Kairos Power’s Hermes 2 plant, scheduled to begin operations in 2030,” said Amanda Peterson Curio, Google’s global head of Data Center Energy, in a blog post on Monday. “In this initial phase of the collaboration, we will procure clean energy attributes from the plant through TVA to help power our data centers in the region with locally sourced clean energy, every hour of every day.”

Hermes 2 received construction approval from the Nuclear Regulatory Commission (NRC) in November 2024 for its original 70-MWth “low-power” two-unit test facility, becoming the first electricity-producing Gen IV reactor permitted for construction in the U.S. How the uprated, single-unit redesign will be treated under NRC licensing has not yet been specified, but the new deal between TVA, Google, and Kairos Power is significant on several more fronts. It marks a major step toward commercializing advanced nuclear technology and offers a new model for how utilities, hyperscalers, and technology developers can collaborate to meet surging power demand from the digital economy.

From Google’s Bet to TVA’s Buy-In

The new TVA–Kairos PPA comes less than a year after Alameda, California–based Kairos and Google unveiled a landmark agreement to develop 500 MW of advanced nuclear capacity by 2035, under a pioneering Master Plant Development Agreement. As POWER reported in detail in October 2024, that agreement was effectively the first corporate commitment in the U.S. to a multi-reactor small modular reactor (SMR) “orderbook.”

Kairos Power has been developing its fluoride salt–cooled high-temperature reactor (KP-FHR) technology since its founding in 2016 under a rapid, iterative approach that combines in-house manufacturing, hardware demonstration, and regulatory engagement to accelerate commercialization. As POWER has reported, Kairos’s KP-FHR comprises a graphite-moderated, “randomly packed” pebble‐bed reactor with molten fluoride salt coolant (a chemically stable molten fluoride salt mixture of 2LiF:BeF2 [Flibe] enriched in Li‐7), operating at high temperature and near‐atmospheric pressure.

The company’s targeted commercial offerings will include the KP-X Commercial Demo Plant, a single-unit, 50-MWe fluoride salt-cooled high-temperature reactor designed to operate at 650C and near-atmospheric pressure, and KP-FHR Commercial Plant, a dual-unit, 150-MWe reactor configuration (2 x 75 MWe) designed for high efficiency with a 650C reactor outlet temperature. Kairos’ designs will use tri-structural ISOtropic (TRISO) particle fuel in pebble form with a carbonaceous‐matrix coated particle design. The fuel will contain high-assay low-enriched uranium (HALEU) enriched at 19.74%.

The company kicked off construction of its first demonstration reactor, Hermes 1, in July 2024, a 35-MWth iterative non-power demonstration molten salt nuclear reactor, in Oak Ridge, Tennessee. When it comes online as anticipated in 2027, Hermes 1 will become Kairos’ first nuclear build. That achievement follows substantial progress on a series of Engineering Test Units (ETUs), which are non-nuclear integrated tests. In tandem, the company has made headway on the production of high-purity fluoride salt coolant for its iterative reactor series.

Hermes 2, the next iteration, represents the first deployment under the company’s landmark agreement with Google. Kairos originally planned Hermes 2 as a 28-MWe design, but on Monday, it said it will increase the reactor’s output to 50 MWe, generated by a single reactor, “to accelerate the delivery of clean energy to Google.” The NRC issued construction permits for the 70-MWth Hermes 2 facility in November at the East Tennessee Technology Park Heritage Center (ETTP) in Oak Ridge, Tennessee. The site, notably, will also host the single 35-MWth Hermes 1 test reactor, a non-nuclear engineering test unit, and potentially a Kairos Power fuel fabrication facility.

Unlike Hermes 1, Hermes 2 is a full, grid-connected reactor designed to demonstrate the complete KP-FHR plant architecture in a power-producing configuration. The reactor will use high-purity molten fluoride salt (Flibe)—a chemically stable mixture of lithium fluoride and beryllium fluoride enriched in lithium-7—as a coolant, and TRISO fuel in pebble form with a carbonaceous-matrix coating to enable high-temperature, low-pressure operation with robust inherent safety. The plant will integrate a Rankine steam cycle for power conversion to validate the KP-FHR’s thermal-to-electric performance at scale.

The PPA with TVA, Kairos suggested on Monday, effectively translates Google’s customer demand signal into regulated market validation, which is a crucial milestone for the company’s commercialization strategy. “This collaboration is an important enabler to making advanced nuclear energy commercially competitive,” said Mike Laufer, Kairos Power CEO and co-founder. “The re-envisioned Hermes 2 gets us closer to the commercial fleet sooner and could only be made possible by close collaboration with TVA and Google, and a supportive local community. We are excited to grow Kairos Power’s operations in Oak Ridge while writing a new chapter in the region’s distinguished nuclear history.”

The Google-Kairos partnership in October 2024 eyed PPAs for power and ancillary services and environmental attributes. It also incorporates a milestone-based accountability process, similar to one Kairos pioneered as part of a $303 million federal award it received under the Department of Energy’s (DOE’s) Advanced Reactor Demonstration Program (ARDP) risk reduction pathway, Kairos has told POWER.

A Pioneering Prospect for TVA

For TVA, the PPA represents another avenue through which the federal corporation will seek to address surging demand from hyperscale data centers. The public power entity already operates seven reactors across three sites, which together supply roughly 40% of TVA’s generation portfolio and furnish it with one of the most significant shares of nuclear in any U.S. system.

TVA’s move to contract power from Hermes 2 comes alongside its own parallel bid to license new small modular reactors (SMRs). In May 2025, TVA became the first U.S. utility to submit a construction permit application to the NRC for the GE Vernova Hitachi Nuclear Energy (GVH) BWRX-300 design, following its receipt of an early site permit (ESP) for the location in 2019. The project, dubbed “CRN-1,” could deliver up to 300 MW gross output and features advanced passive safety systems, modular construction methods, and design lineage from GVH’s fleet of boiling water reactors. While TVA has not explicitly confirmed it will build more reactors at the Clinch River site, the NRC’s ESP for Clinch River allows for “two or more” SMR modules of up to 800 MWe/2420 MWth.

Don Moul, TVA president and CEO, has stressed that the utility is committed to “igniting innovation” and pursuing advanced nuclear to meet explosive regional demand growth. During TVA’s July earnings call, Moul noted that even with the same 96F temperature as the previous June, “this year TVA saw an approximate 500 MW increase in demand,” which he suggested reflects “population growth, economic expansion, and the integration of new electricity-dependent technologies.” TVA’s current planning assumption includes “more than 6,200 MW of new firm, dispatchable generation pending required approvals and environmental reviews,” he noted. “Over 3,500 MW are currently under construction, including investments in the gas fleet at Cumberland, Kingston, and New Caledonia. We also continue to support customer-driven solar and battery storage additions through power purchase agreements.”

To address surging load, TVA continues to “open the aperture on advanced nuclear and set a strong foundation with optionality to deploy advanced nuclear technologies in our country,” Moul said. Clinch River is “uniquely positioned to establish America’s energy dominance to power artificial intelligence, quantum computing, and advanced manufacturing.” More recently in July, TVA signed its first set of commercial contracts with fusion company Type One Energy for Project Infinity, an ambitious effort to develop and deploy a 350-MW fusion power plant in the Tennessee Valley by the mid-2030s.

However, “Developing first-of-a-kind technologies involves substantial costs,” and TVA is ready to work with partners to help commercialize this critical technology,” Moul noted. TVA is notably leading a coalition of industry partners in pursuing $800 million from the Department of Energy’s Gen III+ grant program for development of the BWRX-300 design SMR at Clinch River, he said. What it comes down to is “We’re looking for financial partners to offset that first-of-a-kind cost and not put it on our customers as it launches this industry.”

On Monday, Moul again underscored the utility’s responsibility to ensure reliability and champion innovation. “Energy security is national security, and electricity is the strategic commodity that is the building block for AI and our nation’s economic prosperity,” he said. “The world is looking for American leadership, and this first-of-a-kind agreement is the start of an innovative way of doing business. By developing a technology, a supply chain, and a delivery model that can build an industry to unleash American energy, we can attract and support companies like Google and help America win the AI race.”

Google’s Strategy: Decarbonize Data Centers in Tennessee and Alabama

Under the PPA, Google is meanwhile poised to “receive the clean energy attributes from the plant through the TVA system to further decarbonize its data center operations in Montgomery County, Tennessee, and Jackson County, Alabama, and support future growth in the region,” it said on Monday.

“To power the future, we need to grow the availability of smart, firm energy sources,” said Google’s Global Head of Data Center Energy Corio. “This collaboration with TVA, Kairos Power, and the Oak Ridge community will accelerate the deployment of innovative nuclear technologies and help support the needs of our growing digital economy while also bringing firm carbon-free energy to the electricity system. Lessons from the development and operation of the Hermes 2 plant will help drive down the cost of future reactors, improving the economics of clean firm power generation in the TVA region and beyond.”

As POWER has reported, Google has long been pursuing a 24/7 carbon-free energy (CFE) goal across its global operations by 2030. In its 10th Environmental Report, Google reported a 27% year-on-year increase in electricity consumption across all operations due to growing AI workloads, Google Cloud, YouTube, and other core businesses. The company anticipates the trend will continue, suggesting its electricity use to rise from 24 TWh in 2023 to over 42 TWh by 2030—a roughly 75% increase.

While Google revealed that it purchased more than 8 GW of renewable energy in 2024, it says it recognizes that to operate on a near 100% hourly carbon-free energy basis every hour, every day, in every grid region by 2030, dispatchable clean energy solutions beyond intermittent wind and solar will be required.

“Kairos Power’s SMR design uses a molten salt cooling system and a unique ceramic pebble fuel,” Google’s report notes. “This system allows the reactor to operate at low pressure, simplifying the design and enhancing safety. The company is following an iterative development process, building and testing multiple demonstration units before deploying its first commercial plant. This approach allows for continuous learning and improvement, ultimately leading to a more reliable and cost-effective technology.”

The company’s partnership with Kairos, which calls for the procurement of up to 500 MW of power from an “orderbook” of multiple reactors, will “help accelerate the repeated reactor deployments that are needed to lower costs and bring Kairos Power’s technology to market more quickly,” the report notes. “This is an important part of our approach to scale the benefits of advanced technologies to more people and communities.”

According to Kate Brandt, chief sustainability officer at Google, the company is also banking on enhanced geothermal, piloting a project with Fervo Energy in Nevada that is now producing power for the grid. Google also recently launched a collaboration with Tapestry and grid operator PJM to develop AI-driven data capabilities for a more intelligent and reliable electricity system to speed up grid interconnection, with a goal of making electricity more reliable and affordable for consumers within the grid operator’s 13-state footprint.

However, at the same time, Google is aggressively pushing efficiency gains to temper demand growth. “In 2024, Google data centers used 84% less overhead energy than the industry average. And we’re leading the industry in making AI models better, faster and more efficient, for example through techniques like quantization which have sped up large-language model training efficiency by 39%,” Brandt said. “Ironwood is our seventh-generation and most powerful, capable, and energy efficient Tensor Processing Unit (TPU)—using nearly 30 times less energy than our first Cloud TPU from 2018.”

—Sonal Patel is a POWER senior editor (@sonalcpatel, @POWERmagazine).

Editor’s Note: This story is still developing. Please check back for updates as more details become available.