Nuclear power for data centers, explained: every deal tracked

Nuclear power already supplies data centers, but almost entirely through contracts with reactors that were built decades ago. Amazon, Google, Meta and Microsoft have signed for roughly 8.5 GW of output from operating, restarting and uprated US reactors — an NNN tally of the deals in the table below — while the International Energy Agency counts 45 GW of conditional data-center agreements with small modular reactor projects. The gap between those two numbers is the story: the existing fleet is delivering now, and almost every new reactor promised to a data center is still a framework, an option or a licence application.

Key facts

• Data-center electricity demand rose 17% in 2025 and is set to double by 2030, with AI-focused data centers tripling, according to the IEA
• Amazon Web Services buys up to 1,920 MW from Talen's Susquehanna plant through 2042, the largest nuclear supply contract for data centers
• Microsoft's 835 MW Crane restart (formerly Three Mile Island Unit 1) is on track for 2027, Constellation says
• Meta's nuclear agreements support up to 6.6 GW of new and existing capacity by 2035 — the largest portfolio of any buyer
• Conditional data-center–SMR agreements grew from 25 GW at end-2024 to 45 GW; only Kairos Power's 50 MW Hermes 2 is under construction

How nuclear serves data centers

A data center is a large, persistent electricity load: servers, AI accelerators and cooling draw power day and night, and a single AI campus can need hundreds of megawatts. Nuclear plants run at high capacity factors around the clock, which is why buyers who want firm, low-carbon supply keep returning to them. There are four ways a data center gets nuclear power today:

1. Contract an operating plant. A power purchase agreement (PPA) reserves a share of a reactor's output for 20 years or more, delivered through the grid. This is the only route delivering power at scale today, and the fastest to start — Meta's Clinton deal begins in June 2027, about two years after signing.
2. Fund an uprate or life extension. The buyer's long contract pays for extra output from an existing plant or for another licence renewal. Uprates add new capacity to the grid instead of only reallocating what is there.
3. Restart a closed plant. Crane in Pennsylvania and Duane Arnold in Iowa are being brought back under long contracts with Microsoft and Google. Restarts need NRC approvals, refurbishment and grid rights, and take several years.
4. Build new reactors. SMRs, microreactors and large reactors contracted for data centers. None is operating; the first power is targeted for 2030.

How the power is delivered matters as much as who generates it. Front-of-the-meter deals move power through the grid like any other supply. Co-located or behind-the-meter arrangements take power directly from a neighbouring plant, which reduces grid charges but has drawn regulatory pushback over who pays for the shared network (see the grid rules section below).

The numbers

Existing plants: operating, restarting and uprating for data centers

These are signed contracts with reactors that exist today. Status is as of October 2026.

New reactors planned for data centers

Every project below is tied to a named data-center buyer or developer. "Binding" means a purchase or prepayment contract; "framework" means a master agreement, option or funding-plus-rights deal; MOU and LOI are non-binding.

Two fusion contracts sit alongside these: Microsoft's 50 MW PPA with Helion for the Orion plant in Malaga, Washington, targeting 2028, and Google's 200 MW offtake from Commonwealth Fusion Systems' first ARC plant in Chesterfield County, Virginia. Neither technology has yet put power on a grid — see nuclear fusion, explained.

Who is buying

The pattern is consistent. Hyperscalers sign binding contracts for existing reactors, where power arrives on a known date, and take options, prepayments or development stakes in new ones, where they arrive only if the reactor is licensed, financed and built. Data-center developers without hyperscaler balance sheets lean on the start-up end of the market, where most agreements are non-binding.

The grid rules: co-location and FERC

Putting a data center beside a reactor and taking power directly looked like the obvious shortcut in 2024. Regulators slowed it. On November 1, 2024, the Federal Energy Regulatory Commission rejected, 2–1, an amended interconnection agreement that would have raised the behind-the-meter supply to Amazon's Susquehanna campus from 300 MW to 480 MW. Talen and Amazon then restructured the deal as a front-of-the-meter PPA, effective April 2026.

The broader rules followed. On December 18, 2025, FERC found PJM Interconnection's tariff unjust and unreasonable for lacking co-location provisions and ordered new transmission services for co-located load, including firm and non-firm contract-demand options. A June 18, 2026 rehearing order upheld that framework and required further tariff revisions. The practical effect: co-location is possible in the largest US grid region, but the data center pays for the grid services it still relies on — which narrows the cost advantage of plugging in next door. Restarts face grid limits too: FERC in 2026 let Constellation transfer 760 MW of interconnection rights to Crane, after PJM found that some transmission upgrades could run past 2030.

Common misconceptions

"Data centers are already running on small modular reactors." No SMR supplies a data center anywhere. The only operating SMRs are in China and Russia, and the first Western new-build tied to data centers, Hermes 2, targets 2030. See SMRs, explained.

"A 12 GW or 45 GW announcement means 12 GW or 45 GW is coming." The IEA's 45 GW is conditional offtake, and Switch's 12 GW with Oklo is explicitly non-binding. Binding capacity on the new-build side is a small fraction of the headlines.

"Buying existing nuclear output adds clean power to the grid." Only partly. A PPA with an operating plant reallocates output that was already on the grid unless it pays for an uprate, a restart or a licence extension that would not otherwise happen. That is why recent deals — Clinton, Vistra, Calvert Cliffs, Georgia Power, Loviisa — bundle uprates or relicensing into the contract.

"Nuclear-powered data centers leave the grid." Even co-located campuses depend on the grid for backup when the reactor refuels or trips, which is why FERC now requires co-located load in PJM to buy transmission services.

"New reactors can solve the AI power crunch this decade." A data center can be built in a few years; a first-of-a-kind reactor takes most of a decade. That mismatch is why projects like Blue Energy's Texas plant start with gas turbines and plan to switch to nuclear later.

Siting and public opinion

Power is only part of the local debate. Gallup found 71% of Americans oppose a data center in their area, compared with 53% for a nuclear plant — so the data center, not the reactor, is often the harder sell. Water use, land, transmission lines, noise and electricity bills all shape the response. A reactor on a data-center campus also brings emergency planning zones, security requirements and NRC siting review that a gas plant or a grid connection does not. Most announced new-build projects therefore pick existing energy sites: retired coal plants (Cottam), former federal land (Pike County, Ohio, at the former Portsmouth Gaseous Diffusion Plant) or existing nuclear stations (North Anna, and Cascade near Columbia Generating Station).

Current state (October 2026)

Nuclear for data centers has two speeds. The existing fleet is where the power is: roughly 8.5 GW of US reactor output is now contracted to Amazon, Meta, Google and Microsoft, and new deals increasingly pay for uprates and relicensing rather than plain output. The latest, Amazon's Calvert Cliffs agreement, was signed on September 30, 2026. Two restarts — Crane (2027) and Duane Arnold (Q1 2029) — are funded and under way.

New reactors remain a pipeline. One project tied to data centers is under construction (Hermes 2), one hyperscaler-linked SMR project has an NRC construction permit application in (Blue Energy–Crusoe, part 1), and one large-reactor campus is in NRC review (Fermi America). The largest volumes — Meta–TerraPower, Amazon–X-energy, Switch–Oklo — depend on sites, licences and first-of-a-kind cost performance still to come.

What to watch: Crane's return to service in 2027, the first deliveries under Meta's Clinton and Amazon's Comanche Peak contracts (both 2027), site announcements for Meta's Natrium units, the NRC's review of Blue Energy's application, and whether PJM's new co-location services revive direct-connection deals.

Latest NNN coverage

• Google buys Loviisa nuclear power: 22-year PPA with Fortum to 2050 — September 2026
• Blue Energy files NRC application for Texas gas-to-nuclear plant — September 2026
• DOE closes $1.9B loan to restart NextEra's Duane Arnold plant — September 2026
• Nature Outlook puts SMRs at center of AI power debate — August 2026
• Gallup: 71% oppose local AI data centers, vs. 53% for nuclear — August 2026
• Blue Energy and GVH advance 2.5 GW gas-plus-nuclear plant in Texas — August 2026
• TerraPower names Hyundai E&C as EPC for up to eight Natrium reactors — August 2026
• IEA says data-center SMR deals hit 45 GW — July 2026
• GridMarket, Deployable Energy announce $22.5B data-center nuclear deal — July 2026

Related reading

For the reactors behind the new-build deals, start with SMRs, explained and top SMR developers in 2026, then the design pages for Natrium and the BWRX-300. The licence path every new project still has to walk is NRC reactor licensing, explained; the federal money behind restarts like Duane Arnold is in DOE nuclear funding, explained. For why buyers choose nuclear over gas for firm supply, see nuclear vs natural gas for baseload power.