In Fall 2025, Sierra Club secured settlements in two separate Duke Energy rate cases in South Carolina, winning rate reductions and advancing our work to reduce harmful impacts caused by data centers and other large load electric customers. Duke Energy currently operates two separate subsidiaries in the Carolinas - Duke Energy Progress (DEP) and Duke Energy Carolinas (DEC). The utility filed rate cases in South Carolina earlier this year for both subsidiaries.
In the DEP rate case, the utility originally proposed an increase of over $21 per month for residential customers. As a result of our settlement, the average DEP residential customer will see their bill go up $11 per month instead. Duke had also proposed an increase to the basic monthly service charge, which was eliminated in the final settlement agreement. Through the settlement, Duke agreed to join Sierra Club and other parties in petitioning the Public Service Commission to open a new docket to evaluate the impacts of large loads and consider comments on large load tariff elements, clean transition tariffs, and flexible interconnections.
We navigated similar issues in the DEC rate case, reaching a settlement on December 5. In addition to locking in the requirement to file a joint petition with state utility regulators to open the new docket to address the impacts of new large load customers, we achieved immediate, tangible wins for ratepayers. Duke Energy Carolinas originally proposed a monthly increase of over $10 (7.6%) but was only granted a 0.6% increase, meaning DEC customers will only see their bills increase by $0.84.
Sierra Club was represented in both of these cases by Senior Attorney Josh Berman.