The South Carolina Public Service Commission (PSC) adopted simplified interconnection guidelines for small distributed generation (DG) in December 2006. These guidelines address renewable-energy systems and other forms of DG up to 20 kilowatts (kW) in capacity for residential systems, and up to 100 kW for non-residential systems. Provisions for three-phase generators are not included.
South Carolina's interconnection guidelines apply to three of the state's four investor-owned utilities -- Progress Energy, Duke Energy and South Carolina Electric and Gas. The fourth utility, Lockhart Power, is not subject to the federal Public Utility Regulatory Policies Act of 1978 (PURPA).
There is a $100 application fee for residential systems and a $250 application fee for non-residential systems. Utilities may not require residential customers to carry liability insurance beyond the amount required by a standard homeowner's policy ($100,000 minimum coverage), but non-residential generators are required to carry comprehensive general liability insurance ($300,000 minimum coverage). Generators are responsible only for upgrade and improvement costs associated directly with a system's interconnection, but these costs may be determined by utilities. Utilities are prohibited from imposing indirect fees and charges. The guidelines include a mutual-indemnification requirement.
A redundant external disconnect switch is required, and the capacity of all interconnected generation is generally limited to a maximum of 2% of rated circuit capacity. Utilities must file semi-annual reports with the PSC detailing the number of interconnection requests approved and denied, and the reasons for any denial. There are no procedures for dispute resolution.