In South Carolina, taxpayers may claim a credit of 25% of the costs of purchasing and installing a solar energy system or small hydropower system for heating water, space heating, air cooling, energy-efficient daylighting, heat reclamation, energy-efficient demand response, or the generation of electricity in a building owned by the taxpayer. Effective July 1, 2009, SB 1141 expanded the scope of this credit to include small hydropower systems. Only hydropower systems installed after July 1, 2009 are eligible for the tax credit. HB 3874 of 2016 expanded the scope again to include geothermal energy projects installed between January 1, 2016 and January 1, 2019.

The maximum credit a taxpayer may take in any one tax year is $3,500 for each facility or 50% of the taxpayer's tax liability for that taxable year, whichever is less. Unused credit, or credit that exceeds the annual cap, may be carried forward for 10 years.

The term "system" includes "all controls, tanks, pumps, heat exchangers, and other equipment used directly and exclusively for the solar-energy system." The term "system" does not include any land or structural elements of the building, such as walls and roofs, or other equipment ordinarily contained in the structure.

Solar-thermal systems must be certified by the Solar Rating and Certification Corporation (SRCC) or a comparable entity endorsed by the South Carolina Energy Office to qualify for the credit, unless the system was installed before June 19, 2007.

The South Carolina Department of Revenue has issued forms and instructions for claiming the tax credit.