Elena Voss890 MW. That is the new nuclear capacity Google identified over five years inside a 3,590-MW agreement with Constellation Energy in the PJM grid. The smaller number is about one-quarter of the larger one.
Key takeaways
- The Department of Energy provided a $1.9 billion loan for refurbishment of the 615-MW Duane Arnold plant, which shut in 2020.
- Meta’s 20-year purchase from Constellation’s Illinois nuclear plant begins in mid-2027, when a 10-year state subsidy expires.
- In January 2026, PJM proposed that large data centers bring generation or curtail electricity use to reduce outage risk.
- Google signed arrangements with five utilities for up to 1 GW of potential data-center demand reductions during peak periods.
- PJM cut its summer-2027 peak-load forecast from roughly 164 GW to 160 GW because some proposed projects lacked firm service or construction commitments.
Google and its peers are securing long-term claims on reliable nuclear output and backing plant investments for AI data centers. A buyer can help keep an operating reactor investable without adding that reactor’s full contracted output to the grid. Contracted megawatts and net new, deliverable megawatts must be counted separately.
The headline megawatt measures a purchase, not a build
Google’s agreement puts the distinction in one contract. Google described 890 MW as new nuclear capacity; the remaining roughly 2,700 MW is not identified as new supply. That does not make the larger portion worthless. Output from an operating plant has a different timetable from output that still requires investment. It does mean that 3,590 MW cannot serve as a measure of generation added to PJM.
Meta made the split visible in January. Its 20-year arrangement with Vistra covers more than 2,600 MW from three existing nuclear plants. Meta separately agreed to support reactor projects with TerraPower and Oklo. The Vistra purchase concerns plants already in the fleet; the developer agreements concern power that still has to be built.
Neither purchase agreement, on the disclosed facts, establishes that a data center can draw the contracted quantity at a particular hour or location. Plant output, transmission access, and service to a new load are related questions.
Constellation can attach a customer to a plant decision
In September 2024, Microsoft agreed to buy all output from Constellation’s proposed Three Mile Island restart under a reported 20-year arrangement covering 835 MW. Constellation planned $1.6 billion for the restart and refurbishment. The plant was shut; its output depended on work still to be done.
In June 2025, Meta agreed to buy power from Constellation’s Illinois nuclear plant for 20 years beginning in mid-2027, when a 10-year state subsidy expires. Meta’s contract gives the operating plant a buyer as state support ends, though the reporting does not establish what the plant would otherwise have done.
In October 2026, Amazon agreed to buy 690 MW for 20 years while Constellation planned more than $3 billion of investment to increase capacity at its Maryland nuclear plant. That plan would expand an operating asset rather than build a reactor at a new site.
Existing plants, restarts, and new reactors run on different clocks
An operating reactor can sell output now. A restart must clear refurbishment and operating hurdles. A new reactor must clear approvals and construction as well. Grouping all three as “AI nuclear power” obscures the date at which each could serve additional load.
Google’s other nuclear arrangement shows the middle clock. Its 25-year deal with NextEra Energy includes a restart of the 615-MW Duane Arnold plant in Iowa, which shut in 2020. The Department of Energy later provided a $1.9 billion loan for refurbishment. As with Three Mile Island, a buyer and public financing support the attempt to return an existing site to service. Neither turns a planned restart into operating output.
At the longest-dated end, Meta’s developer arrangements include support for an Oklo campus designed to scale to 1.2 GW and TerraPower projects targeting delivery as early as 2032. Oklo targets first units around 2030, subject to approvals. Oklo is also building a reactor in Idaho; reporting counted an estimated 22 active US reactor projects in August 2026. A project pipeline records work under way, not power already available to a grid operator.
Grid operators must wait through the capacity lag of a restart’s refurbishment or a new reactor’s approvals, construction, and connection before either produces power.
PJM is asking what the buyer brings to the grid
At warehouse scale, a data center’s maximum power draw shapes the facility that must be built, while its actual use varies with load. Reliable electricity is therefore an input to computing-system availability, not a peripheral facilities purchase. A contract with a generator addresses part of that need; the grid must still be able to serve it.
In January 2026, PJM proposed requiring large data centers to bring their own generation or curtail electricity use to reduce outage risk. Google subsequently signed arrangements with five utilities for up to 1 GW of potential reductions in data-center consumption during peak periods. Curtailment can relieve the system when capacity is tight without creating another megawatt of supply.
Google, Microsoft, Meta, Amazon, OpenAI, and other companies also pledged to bear the cost of new generation for their data centers. The pledge states who should pay. PJM’s proposal asks what a large load can actually do when the grid is stressed. A buyer that cannot connect, finance supply, or manage demand has a problem that a clean-energy label cannot settle.
A long contract still leaves a term sheet to inspect
A 20-year customer commitment can improve the revenue case for a capital project. Three Mile Island also received a $1 billion Department of Energy loan, alongside Microsoft’s reported offtake and Constellation’s planned investment. Corporate demand and public credit can occupy different places in the same capital stack.
The published accounts of the Constellation agreements do not disclose a comparable set of prices, take-or-pay obligations, termination rights, credit support, or construction- and delivery-risk terms. Without them, a reader cannot tell how much risk the buyers have taken off generators’ or lenders’ books. That is also the test for AI data-center project finance: a long-dated customer agreement matters to investment only to the extent that its obligations survive delay, cost overruns, and changes in demand.
PJM reduced its summer-2027 peak forecast from roughly 164 GW to 160 GW because some proposed projects, including data centers, lacked firm service or construction commitments. SemiAnalysis separately reported that Microsoft froze about 1.5 GW of data-center projects slated for 2025–26 and walked away from more than 2 GW of non-binding contracts. Those reports do not say Microsoft abandoned its Three Mile Island agreement. They show why a proposed load needs scrutiny before a generator builds against it.
Frequently asked questions
Which plants or investments make up Google’s 890 MW of identified new nuclear capacity?
The disclosed account identifies 890 MW as new capacity over five years but does not provide an asset-by-asset breakdown. It therefore cannot show which individual plant upgrades, restarts, or other investments account for that figure.
When will Google’s 890 MW actually be available to the grid?
Google placed the capacity on a five-year clock, but the available information gives no unit-specific in-service dates. Identified capacity is not the same as operating output at a generator’s meter.
How much financial or construction risk did Google take on in the Constellation agreement?
That cannot be determined from the published accounts. They do not disclose prices, take-or-pay commitments, termination rights, credit support, or construction- and delivery-risk allocation.
Can a nuclear offtake agreement by itself ensure power reaches a particular data center?
No conclusion can be drawn on the disclosed facts. The agreements do not establish service to a specific load at a particular hour or location, which also depends on plant output and transmission access.
Nuclear contracts span operating output, restarts, and capacity additions
| Buyer and seller | Contracted power | Asset or capacity status | Term, timing, or investment |
|---|---|---|---|
| Google–Constellation | 3,590 MW | 890 MW identified as new nuclear capacity | New capacity identified over five years |
| Meta–Vistra | More than 2,600 MW | Output from three existing nuclear plants | 20 years |
| Microsoft–Constellation, Three Mile Island | 835 MW | Proposed plant restart | Reported 20 years; Constellation planned $1.6 billion for restart and refurbishment |
| Amazon–Constellation, Maryland plant | 690 MW | Operating plant with a planned capacity increase | 20 years; Constellation planned more than $3 billion of investment |
Google’s 890 MW belongs on the supply side of that scrutiny, but on a five-year clock. It is capacity identified for addition, not a reading at a generator’s meter. The 3,590-MW contract is already a purchase; the smaller number still has to become power.