Amazon has signed a power purchase agreement to offtake energy from Maryland's only nuclear plant.

Constellation Energy and Amazon this week announced a long-term agreement that will support the continued investment in and expansion of the 1.78GW Calvert Cliffs Clean Energy Center, located in Lusby, Calvert County.

The 20-year agreement totals 690MW of capacity and will enable more than $3 billion in infrastructure investment, including improvements across the plant and approximately 190MW in total of new generating capacity coming online between 2030 and 2032.

The parties have also entered into a related retail supply agreement to support Amazon operations in the 13-state PJM market.

"This agreement demonstrates how private investment can strengthen critical energy infrastructure," said Joe Dominguez, chairman, president, and CEO of Constellation. "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."

"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."

Amazon was previously planning to develop a large-scale data center campus next to the nuclear plant, but pulled out of the project in August. Documents suggest the firm had been hoping to develop more than 2.46 million sq ft (228,540 sqm) of data center space across eight buildings, totaling around 500MW of capacity.

The cloud company is developing another campus in Maryland at TPG’s Quantum Frederick Park in Adamstown, just over the border from Loudoun County in Virginia.

The firm recently bought an office and data center site outside Baltimore in a sale-leaseback deal with asset manager T. Rowe.

Amazon has also been looking to develop a cable landing station in Maryland, but those plans are also facing difficulties. The cloud company’s upcoming Fastnet cable is set to connect the US to Ireland, landing in Maryland’s Ocean City, but local moratoriums against data centers have been brought into effect.