Meta's Clinton Nuclear PPA: 1,121 MW From Constellation Starting June 2027

Meta's 20-year nuclear power purchase agreement (PPA) for 1,121 MW from Constellation's Clinton Clean Energy Center in Illinois starts in June 2027, as state zero-emission credit support ends, Constellation said when announcing it on June 3, 2025.

The arrangement keeps an existing reactor running rather than building a new one. That matters for a data-center buyer because the megawatts already exist: the plant has run since 1987, the Nuclear Regulatory Commission renewed its licence in December 2025, and no first-of-a-kind construction stands between Meta and the supply. What Meta buys, according to Constellation, is the plant's clean energy attributes, counted toward its goal of matching all of its electricity use with clean power. The electricity itself keeps flowing onto the regional grid rather than to a Meta campus. Clinton was also named on Oct. 27, 2026 as one of eight Constellation plants in a conditional federal loan for uprates, according to ANS Nuclear Newswire.

Clinton Boiling Water Reactor and the 30 MW Uprate

Clinton unit 1 is a single boiling water reactor, a design in which water boils inside the reactor vessel and the steam drives the turbine directly. World Nuclear News lists it at 1,062 MWe net and says it was connected to the grid in April 1987. The agreement's 1,121 MW figure is Constellation's own, and the company did not say whether it includes the extra output from the uprate. Constellation's own Clinton plant page lists the reactor at up to 1,092 MW; the 1,062 MWe net, up to 1,092 MW and 1,121 MW figures come from different documents and are not reconciled here.

An uprate raises an operating plant's output without building a reactor. Constellation said the Meta deal will add 30 MW at Clinton this way. Constellation's release gives no completion date for the 30 MW and cites no NRC uprate application.

PPA Terms, Jobs and the DOE Loan

The parties signed a power purchase agreement (PPA), a signed contract to buy the plant's output or its attributes for a set term, here 20 years from June 2027. Neither company disclosed the price. Constellation called the PPA a market-based solution that "essentially replaces" the zero-emission credit program created by Illinois' Future Energy Jobs Act, which rescued Clinton after it was slated for closure in 2017 following years of losses. Constellation puts the end of that support at mid-2027; World Nuclear News gives May 2027.

Constellation said the agreement preserves 1,100 local jobs and about $13.5 million in annual tax revenue, and adds $1 million in charitable giving over five years from 2026. The company also said it is investing more than $370 million to relicense Clinton and its Dresden plant together, including two new auxiliary transformers and two equipment chillers at Clinton, World Nuclear News reported.

Federal money is not yet in hand. The Department of Energy's loan of up to $5 billion for uprates at eight Constellation plants, Clinton among them, is a conditional agreement, ANS reported, and the sources do not say how much of it would go to Clinton. Voltgrid News reported earlier on the DOE's Constellation uprate loan; it is not a final loan.

Clinton Licence Renewal Timeline to 2047

Constellation applied to renew Clinton's operating licence on Feb. 14, 2024. The NRC's schedule shows the safety evaluation issued on Aug. 29, 2025 and the final supplemental environmental impact statement (SEIS) on Aug. 1, 2025, with the decision by the director of reactor regulation on Dec. 16, 2025, later than the Oct. 9, 2025 date first scheduled. The renewed licence now runs to April 2047, according to World Nuclear News.

Renewal is permission, not a promise. Constellation said at the time that actual operation depends on each plant's financial viability, and that the Meta agreement is what secures Clinton. The company is also weighing whether to extend the site's early site permit or seek a new construction permit for an advanced reactor or small modular reactor (SMR) at Clinton; it has announced no decision.

Why Clinton Has Three Megawatt Figures

Clinton unit 1 is a boiling water reactor that World Nuclear News rates at 1,062 MWe net; Constellation's plant page lists up to 1,092 MW, and its Meta release counts 1,121 MW under the PPA. They come from different documents and Constellation does not reconcile them, so they are not one rating to add or compare.

A PPA prices a contract quantity. Constellation says Meta buys the plant's clean energy attributes while power keeps flowing onto the local MISO zone 4 grid, and that the deal essentially replaces Illinois's ZEC support, which runs to mid-2027. The change is financial, not a new line to Meta.

What the Clinton PPA Means for Meta and the MISO Grid

Clinton was Meta's first nuclear agreement, and Meta says it helped extend the plant's life by 20 years. Its later 20-year agreements with Vistra cover more than 2.1 GW from the Perry and Davis-Besse plants in Ohio, Meta said in January 2026. Both follow the same pattern: paying to keep and expand existing reactors rather than waiting on new designs.

For the grid, the main effect is that Clinton's output stays in the Midcontinent Independent System Operator's zone 4, covering central and southern Illinois, after mid-2027. Meta buys the plant's clean energy attributes while the power flows onto the local grid.

What to Watch Before June 2027

The first date is June 2027, when supply under the PPA begins and state support ends. Before then, watch for Constellation's third-quarter 2026 results, a Clinton uprate filing at the NRC, and whether the conditional DOE loan reaches financial close. A decision on an SMR or advanced reactor permit at the site would be a separate project.