FERC has rejected an amended interconnection agreement that would have supported an Amazon Web Services data center connected to the 2,520 MW Susquehanna nuclear power plant in Pennsylvania. The proposal sought to modify an interconnection service agreement to increase the data center’s co-located load from 300 MW to 480 MW. The FERC decision centers on whether the agreement to increase capacity of the data center located on the site of a nuclear generating facility could raise power bills for the public and affect grid reliability.

Two of the largest utilities in PJM challenged the proposed interconnection agreement. They argue the plan could set a precedent to allow certain large loads to benefit from transmission resources without paying corresponding costs – and that this could harm the market by giving incentives for large loads to disconnect from PJM’s grid, thus raising replacement costs and burdens for other customers.

Co-location issue is a new issue for the Commission. FERC is looking at it more broadly and convened a technical conference on the issue.