Calvert Cliffs nuclear expansion will add 190MW under a new 20-year agreement involving Amazon and Constellation Energy. The program will support more than $3 billion in infrastructure investment across Maryland’s only nuclear plant. The additional generation should enter service between 2030 and 2032. The deal follows Amazon’s withdrawal from its proposed data center campus beside Calvert Cliffs.
Calvert Cliffs nuclear expansion gains new capacity
The project will increase Calvert Cliffs’ generating capacity from 1,790MW to approximately 1,980MW. Constellation owns and operates the nuclear facility in Lusby, Maryland.
The 190MW increase represents an uprate of the existing nuclear plant. The expansion will not require Amazon to connect directly to the facility.
Instead, Calvert Cliffs will continue supplying electricity to the PJM regional grid. Amazon will receive power through a separate long-term arrangement covering 690MW.
The 20-year agreement also includes a retail supply arrangement for Amazon’s regional operations. PJM serves 13 states and the District of Columbia.
The new capacity should provide enough electricity for approximately 147,000 homes. The wider facility already generates enough electricity for more than 1.3 million homes.
Constellation expects the agreement to provide revenue certainty for further plant investment. The company also plans to pursue another 20 years of operating licenses.
The Nuclear Regulatory Commission lists the existing licenses through 2034 and 2036. The agreement therefore supports longer-term planning for both reactors.
As the US nuclear sector explores new ways to expand reliable power generation, Deep Fission’s mile-deep nuclear reactor project in Kansas offers another approach to advanced nuclear construction. The project involves installing a small modular reactor deep underground at the Great Plains Industrial Park in Parsons.
Calvert Cliffs nuclear expansion follows data center withdrawal
Amazon previously planned the Calvert Technology Center near the nuclear plant. Amazon Web Services submitted its conceptual site development application in May 2026.
However, AWS formally withdrew the application on August 4, 2026. Calvert County confirmed the withdrawal through an official public notice.
The county later imposed a six-month moratorium on data center site-plan approvals. The moratorium became effective on August 28, 2026.
County officials cited potential land-use, infrastructure and environmental impacts. Those concerns included electricity, water, wastewater, stormwater, noise and heat.
The withdrawn development therefore ended Amazon’s immediate plan for a hyperscale campus at Calvert Cliffs. The new nuclear agreement creates a different infrastructure investment route.
The Wall Street Journal reported that community opposition contributed to Amazon abandoning the data center plan. Amazon has now shifted its immediate focus toward supporting additional nuclear generation.
The new arrangement represents Amazon’s first nuclear uprate project. An uprate increases electricity production from an existing nuclear facility.
Amazon will support the investment while receiving long-term access to electricity from Constellation. The electricity from Calvert Cliffs will remain available through the regional grid.
Calvert Cliffs nuclear expansion creates future development options
The agreement could support additional nuclear development at the Calvert Cliffs site. Constellation and Amazon are evaluating advanced nuclear technologies for future projects.
Those options could include new reactors and small modular reactors. However, neither company has announced a final investment decision for additional reactors.
The immediate construction program remains the 190MW uprate and plant improvements. Constellation has not yet identified the contractors responsible for the work.
The $3 billion figure represents infrastructure investment enabled by the agreement. The companies have not disclosed the specific financial terms of Amazon’s power purchase agreement.
Calvert Cliffs currently produces approximately 80% of Maryland’s clean energy. The facility employs more than 800 people and contributes about $21 million annually in taxes.
The new investment could therefore extend the plant’s economic and energy role. It also provides additional carbon-free generation for the wider PJM system.
The project comes as technology companies seek dependable electricity for expanding artificial intelligence infrastructure. Amazon has also pursued nuclear power arrangements at other U.S. facilities.
However, the Calvert Cliffs agreement differs from the withdrawn Maryland data center proposal. It supports generation infrastructure without attaching Amazon’s computing campus directly to the nuclear plant.
Project Fact Sheet
Project: Calvert Cliffs Clean Energy Center expansion and nuclear capacity uprate.
Location: Lusby, Calvert County, Maryland, United States.
Existing capacity: 1,790MW.
Additional capacity: Approximately 190MW.
Future capacity: Approximately 1,980MW.
Investment enabled: More than $3 billion.
Power agreement: 20 years.
Amazon power allocation: 690MW.
New capacity delivery: Expected between 2030 and 2032.
New generation: Emissions-free nuclear electricity.
Electricity market: PJM Interconnection.
Grid arrangement: Calvert Cliffs will continue supplying the regional grid.
Residential equivalent: Approximately 147,000 homes from the new 190MW capacity.
Existing residential equivalent: More than 1.3 million homes.
Maryland contribution: Approximately 80% of the state’s clean energy.
Existing workforce: More than 800 employees.
Annual local taxes: Approximately $21 million.
Reactor licenses: Current licenses expire in 2034 and 2036.
Relicensing objective: Support another 20 years of plant operations.
Future technology: Advanced nuclear and small modular reactors under evaluation.
Former development: Calvert Technology Center data center.
Former developer: Amazon Web Services.
Data center moratorium: Six months from August 28, 2026.
Current project status: Nuclear expansion agreement announced September 30, 2026.
Project Team
Owner and operator: Constellation Energy.
Power purchaser: Amazon.
Cloud and data center division: Amazon Web Services.
Regional transmission operator: PJM Interconnection.
Nuclear regulator: U.S. Nuclear Regulatory Commission.
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