Walmart Signs 176 MW Nuclear Power Agreement with Constellation in Illinois

Walmart has entered into a long-term nuclear power purchase agreement with Constellation Energy to supply electricity for its operations in Illinois, reflecting growing corporate interest in round-the-clock, low-carbon power.

The agreement covers approximately 176 megawatts of wholesale electricity supply from Constellation’s Dresden Clean Energy Center near Morris, Illinois. Walmart will purchase electricity, generation capacity, and associated environmental attributes under two separate 15-year contract terms beginning in 2029 and 2030.

Around 30 MW of the contracted capacity will come from planned upgrades to the plant’s existing reactors. These upgrades, known as nuclear uprates, involve improving equipment and operational efficiency to increase electricity generation without constructing a new nuclear facility.

Constellation said the additional generation enabled by the agreement would be sufficient to supply the equivalent of more than 25,000 homes annually. The precise financial terms of the contract were not disclosed.

Agreement Supports Walmart’s Illinois Electricity Demand

The electricity covered by the PPA will be delivered through the regional power grid rather than directly from the nuclear plant to individual Walmart buildings. It will support the retailer’s stores, distribution centres, fulfilment facilities and other operations in Illinois.

By purchasing the electricity and its environmental attributes, Walmart can account for the contracted low-carbon generation as part of its operational energy and emissions strategy, subject to applicable greenhouse gas accounting rules.

Walmart has set a target of reaching zero emissions across its global operations by 2040 and has previously aimed to power its facilities with 100% renewable energy by 2035. The nuclear agreement broadens its procurement strategy beyond renewable technologies such as solar and wind.

The distinction is important because nuclear power is generally classified as a low-carbon or emissions-free source of electricity rather than renewable energy. The contract may therefore support Walmart’s operational emissions target, even though it does not directly advance a renewable electricity target under definitions that exclude nuclear generation.

Walmart reported that renewable sources supplied nearly half of its global electricity needs in 2024. However, the company also acknowledged that it expected to miss some of its nearer-term emissions objectives, including its 2025 emissions target.

The new contract illustrates how large electricity buyers are increasingly combining renewable energy purchases with other sources of low-carbon generation to address reliability, cost and emissions simultaneously.

Uprates Add Capacity Without Building a New Reactor

The Dresden Clean Energy Center operates two boiling-water reactors with combined generating capacity of up to approximately 1,845 MW, according to Constellation. The facility produces enough electricity to serve the equivalent of nearly 1.4 million homes.

Unlike an agreement that only reallocates the environmental attributes of existing generation, the Walmart contract is expected to support incremental output through the planned 30 MW uprate.

Nuclear uprates can involve replacing turbines, generators, pumps and other equipment, as well as improving the efficiency of reactor systems. Although uprates are generally less complex and capital-intensive than building a new reactor, they still require engineering work, investment and regulatory approval.

For corporate buyers, supporting additional generation can strengthen the environmental case for a power purchase agreement by demonstrating that the transaction contributes to an increase in low-carbon electricity supply.

The remaining contracted volume will come from the plant’s existing generation. The agreement therefore combines additional capacity with long-term support for an operating nuclear asset.

In December 2025, the U.S. Nuclear Regulatory Commission renewed the operating licences for Dresden Units 2 and 3 for a further 20 years. The renewed licences allow Unit 2 to operate until December 2049 and Unit 3 until January 2051, providing sufficient operating life to cover Walmart’s 15-year contract periods.

Corporate Nuclear Procurement Expands Beyond Technology Companies

The Walmart agreement is part of a wider increase in corporate procurement of nuclear power in the United States.

Several of the most prominent recent contracts have involved technology companies seeking large quantities of continuous electricity for data centres and artificial intelligence infrastructure. Constellation previously signed a 20-year agreement to supply Meta with 1,121 MW from its Clinton Clean Energy Center in Illinois.

Microsoft has also entered into a long-term agreement supporting the planned restart of a reactor at the former Three Mile Island site in Pennsylvania, now called the Crane Clean Energy Center.

Walmart’s participation indicates that demand for nuclear PPAs is extending beyond the technology sector. Retailers, manufacturers, logistics companies and other businesses with large property portfolios can also benefit from long-term access to predictable and continuously available low-carbon electricity.

Corporate clean energy contracting in the United States reached a record 27 GW in 2025 across technologies including wind, solar, nuclear, geothermal and other low-carbon resources, according to the Clean Energy Buyers Association.

Implications for Energy Buyers and the Illinois Grid

For Walmart, a 15-year agreement can provide greater certainty over part of its future electricity costs and reduce its exposure to changes in wholesale markets. The contract also supports the company’s stated priorities of improving energy reliability and strengthening operational resilience.

For Constellation, the PPA creates a long-term source of revenue that can help justify investment in plant upgrades and support the continued operation of the Dresden facility.

The contract may also benefit the wider Illinois electricity system. Nuclear plants produce steady output and are not dependent on weather conditions, allowing them to complement increasing levels of wind and solar generation. Maintaining existing reactors can also help avoid the short-term increase in fossil fuel generation that may occur when nuclear capacity closes before sufficient replacement resources are available.

However, nuclear procurement also involves considerations that companies must assess carefully. These include the treatment of nuclear environmental attributes in emissions reporting, long-term contract exposure, plant performance, regulatory risk, radioactive waste management and stakeholder views on nuclear energy.

The Walmart and Constellation agreement demonstrates how corporate energy procurement is evolving from a focus primarily on renewable electricity certificates and solar or wind PPAs towards a broader portfolio of low-carbon technologies.

For major energy users, future procurement strategies are increasingly likely to combine variable renewable generation, storage, nuclear power and demand management. The objective is not only to reduce reported emissions, but also to secure reliable electricity as businesses expand and electrify their operations.

Source: ESG Dive