Constellation announced on September 30 a long-term power purchase agreement with Amazon that supports a 190-megawatt uprate at the Calvert Cliffs nuclear power plant in Lusby, Maryland.
Calvert Cliffs has two pressurized water reactors. Unit 1 entered commercial operation in 1975 and Unit 2 in 1977. The plant's net capacity is 1,788 megawatts, so the planned uprate adds about 10 percent. The size places the project in the extended power uprate category, which generally involves significant changes to major balance-of-plant equipment such as high-pressure turbines, condensate pumps, main generators and transformers.
The agreement covers 690 megawatts of power, including the 190 megawatts from the uprate. Constellation said the deal comes with more than $3 billion in Maryland infrastructure investment, including improvements across the plant. All of the electricity continues to flow onto the PJM regional grid, and Amazon will draw the power for its facilities in the region. The arrangement does not involve a data center built beside the plant. Amazon had planned a data center campus around Calvert Cliffs, and that project was dropped in August.
Constellation said the revenue certainty from the agreement supports its work on relicensing. The operating licenses for the two units were renewed in 2000 and run to 2034 and 2036. The company also said the agreement allows progress toward development of new power plants at the site, without giving specifics.
The deal is Amazon's first nuclear uprate agreement. In 2024 the company announced partnerships with X-energy and with Dominion Energy that target a combined 5 gigawatts of nuclear capacity by 2039, and it holds a separate arrangement with Talen Energy tied to the Susquehanna plant in Pennsylvania. Google has agreed to support uprates at Southern Nuclear's Vogtle and Hatch plants, and Meta and Microsoft have also signed nuclear agreements.
Source: ANS Nuclear Newswire - https://www.ans.org/news/2026-10-01/article-8452/amazon-constellation-partner-for-calvert-cliffs-uprate/