On June 17, 2021, the South Carolina Public Service Commission (PSC) voted 4-2 to reject the integrated resource plans (IRP) submitted by two Duke Energy subsidiaries, Duke Energy Carolinas and Duke Energy Progress.[1] The decision comes ten months after Duke filed its IRPs with regulators in North and South Carolina. The IRPs outlined six pathways for its electricity mix under different carbon policy scenarios. Duke favors the base case without strict carbon regulations. Under this pathway, Duke would add about 8.6 GW of solar and more than 1 GW of storage by 2035. The utility would also add 9.6 GW of new natural gas and close its remaining coal plants.

According to the PSC, Duke’s IRPs failed to meet the standards set in the state’s 2019 Energy Freedom Act, which aims to boost clean energy technologies by requiring utilities to consider procuring all sources of electricity generation. The commission questioned the modeling Duke used to project future natural gas prices as well as its estimation of the ability of solar to meet the state’s energy needs. The PSC’s directive asks the utility to make several changes to its plan related to modeling and energy price forecasts. The PSC requests that Duke’s assessments include 20-year Purchase Power Agreements for third-party solar priced at $38/MWh as a selectable resource, with additional PPA pricing at $36/MWh and $40/MWh. These prices are roughly on par with other 20-year PPAs in the region. A more detailed order is expected in the coming weeks. Once the order is out, Duke will have 60 days to file its modified IRP, followed by a 60-day comment and review period. The PSC then has 60 days to approve or reject the modified IRP.

[1] https://dms.psc.sc.gov/Attachments/Matter/f30b83c7-3382-4d64-b0b6-b59712378b3d