Amazon Locks In 20-Year Nuclear Deal With Constellation to Expand Calvert Cliffs

Amazon has signed a 20-year power purchase agreement with Constellation Energy covering 690 MW of output from the Calvert Cliffs Clean Energy Center in Maryland, the companies said, a deal that also unlocks $3 billion in investment to physically expand the plant’s capacity.

The agreement pairs the long-term power contract with a related retail supply deal covering Amazon’s operations across the 13-state PJM grid, the regional transmission system that spans the mid-Atlantic and stretches as far as Illinois. Calvert Cliffs currently produces 1,790 MW and supplies roughly 40% of Maryland’s electricity and about 80% of the state’s clean power.

A physical expansion, not just a contract

Unlike some corporate clean-power deals that simply rebundle existing generation, this one is tied to new capacity. Constellation plans to use the investment to add 190 MW to Calvert Cliffs’ two reactor units, with the additional output expected between 2030 and 2032. The upgrade would lift the plant’s total capacity to roughly 1,980 MW.

Constellation also said the revenue certainty from Amazon’s commitment supports its case for relicensing both Calvert Cliffs units for another 20 years of operation — they were originally licensed to run until 2034 and 2036 — and for studying up to 2,000 MW of next-generation nuclear capacity at the same site.

Why Amazon is doing this now

Amazon Web Services has been racing to secure firm, round-the-clock power for data centers as AI workloads drive electricity demand in PJM territory higher than grid planners had forecast just a few years ago. “Amazon is committed to investing in carbon-free energy to strengthen the grid and benefit communities,” said Kerry Person, AWS vice president of global operations, in a statement.

Constellation chairman and chief executive Joe Dominguez framed the deal in similar terms, saying it “demonstrates how private investment can strengthen critical energy infrastructure.” The agreement follows Constellation’s earlier nuclear power deals with Microsoft, tied to the restart of a Three Mile Island unit, and with Meta, extending the pattern of hyperscale tech companies turning directly to nuclear operators rather than relying solely on the wholesale market.

Part of a wider scramble for firm power

The Amazon deal lands in the same week as other signs of strain in the data-center-driven power market: the NRC has completed its environmental review for the restart of Three Mile Island Unit 1, and regulators elsewhere have pushed back on requests from newer nuclear developers — FERC, for instance, rejected Oklo’s bid to rejoin PJM’s interconnection queue in Virginia — underlining how contested grid access has become as both established reactors and new entrants compete for a limited number of interconnection slots.

Financial terms of the retail supply portion of the Amazon-Constellation deal were not disclosed.

Sources

• World Nuclear News, “Constellation, Amazon agree nuclear-focused power purchase deal,” October 2026 — deal structure, capacity figures, company quotes.
• Bloomberg, “Amazon Nuclear Deal to Help Expand Constellation’s Maryland Site,” September 30, 2026 — investment figure and timeline.
• Maryland Daily Record, “Large upgrade planned at MD nuclear plant under Amazon deal,” October 1, 2026 — Calvert Cliffs output share of Maryland’s grid.

Illustrative image. Photo: Fischer.H, CC BY-SA 4.0, via Wikimedia Commons — source