Amazon signed a 20-year power purchase agreement with Constellation Energy for uprated capacity at Maryland nuclear reactors, securing long-term carbon-free power for East Coast data center operations.
Constellation, a major nuclear power operator, has signed a 20-year power purchase agreement with Amazon to support the continued operation and expansion of the Calvert Cliffs Clean Energy Center nuclear plant in Lusby, Maryland.
The agreement will enable more than $3 billion in infrastructure upgrades to the 1,790-MW facility and add approximately 190 MW of new emissions-free generating capacity through plant uprates scheduled to come online between 2030 and 2032. Constellation and Amazon have also finalized a retail supply agreement to match Amazon's power consumption across the 13-state PJM market.
Constellation emphasized that all electricity generated by the Calvert Cliffs plant will continue to flow into the main grid interconnection. While most corporate PPAs do not directly power the companies that sign them, these investments strengthen the overall supply of carbon-free energy on the grid.
"This agreement demonstrates how private investment can strengthen critical energy infrastructure," said Constellation CEO Joe Dominguez. "Amazon's commitment supports the long-term operation of Calvert Cliffs for generations to come and creates a strong foundation for future investment in both the facility and in advanced nuclear technologies."
The sustained revenue stream enables Constellation to meet its commitment to relicense the plant for another 20 years. Calvert Cliffs is Maryland's only nuclear plant and generates roughly 80% of the state's carbon-free energy. The facility contains two pressurized water reactors with a combined capacity of 1,756 MW. In 2025, Constellation invested $100 million in the plant as the eastern U.S. power generation sector increasingly focuses on nuclear energy.
For Amazon, the 20-year agreement locks in a predictable per-megawatt-hour rate, helping the company manage volatile energy costs for its regional data centers and facilities.
"Amazon is committed to investing in carbon-free energy to strengthen the grid and benefit the communities where we operate," said Kerry Person, vice president of AWS global operations and data center delivery. "This long-term agreement with Constellation sustains the continued operation and expansion of Maryland's largest source of carbon-free energy, supports hundreds of jobs and brings significant new generation to the regional grid."
Similar agreements highlight a broader pattern among technology hyperscalers. In 2025, Constellation signed a 20-year PPA with Meta for output from its Clinton Clean Energy Center in Illinois, securing 1.12 GW of carbon-free power through the 2040s for a plant previously facing early retirement. In 2024, Constellation signed a 20-year PPA with Microsoft to restart Three Mile Island's Unit 1 reactor in central Pennsylvania—a facility that shut down in 2019 for economic reasons but will now support Microsoft's net-zero emissions goals.
These agreements reflect a broader industry trend: as artificial intelligence infrastructure demands accelerate, major technology companies are securing large quantities of baseload, carbon-free power from existing nuclear assets rather than investing in new capacity construction.