Three different kinds of utility, three different answers
The Public Service Commission approved solar choice metering rates for Duke Energy Carolinas, Duke Energy Progress and Dominion Energy South Carolina, available to consumers applying for new service on or after June 1, 2021 and available for ten years.
Santee Cooper is a state-owned utility and follows its own approach. It does not provide one-to-one net metering, and credits customer-generated energy that is consumed by the customer at the full retail rate. Act 90 of 2021, effective after January 1, 2022, brought Santee Cooper under the purview of the South Carolina Public Service Commission.
South Carolina is also served by electric cooperatives, which are a third category again. So the question is not simply whether you are in South Carolina, it is which of these serves your specific address.
Read the name on your electricity bill before applying any figure from an article, a calculator or a neighbour. In a state with this many different arrangements, that is the step that decides whether the rest of your research is relevant.
The questions to put to your own utility
Ask how exported electricity is credited for a new residential solar customer at your address, and whether the value varies with the time of day. Under solar choice metering the value of exported power is tied to time-of-use rates, and that changes how a system should be designed.
Ask what limit applies to system size and how it is calculated, and whether there is an interconnection application fee or any additional metering required.
Ask whether the arrangement you would join is fixed for a period. The solar choice rates approved by the Commission are available for ten years, which is a meaningful horizon to know about when weighing a twenty-five year asset.
Get the answers in writing, then ask your installer which arrangement their savings projection assumes. A projection that names no utility and no tariff is not a projection about your household.
One thing that applies whoever bills you
The South Carolina state income tax credit does not depend on your utility. It is 25 percent of total system cost, up to a total credit of $35,000, claimed on Form TC-38 with your South Carolina return.
The annual limit is what determines its real value: you may use only $3,500 of the credit in a year, or 50 percent of your state tax liability, whichever is less, with a 10 year carryforward for the excess.
Ask a tax advisor how much of the credit you would realistically use given your own liability, since a household with modest liability may not exhaust it within the carryforward period.
And note the federal position has changed. The 30 percent Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit.
The state credit, and how much of it you will actually use
South Carolina offers a state income tax credit of 25 percent of the total system cost, up to a total credit of $35,000, claimed on Form TC-38. That headline is genuinely generous and it is the main reason solar still works here now that the federal residential credit has gone.
The limit that decides what it is worth to you is annual. A taxpayer may use only $3,500 of the credit in a year, or 50 percent of their state tax liability, whichever is less, and the excess for each facility can be carried forward for 10 years.
So a household with modest South Carolina tax liability may not use the whole credit within the carryforward period. That is not a reason to avoid it, but it does mean the number in a sales presentation and the number you receive can differ substantially. Ask a tax advisor how much you would realistically realise given your own liability.
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit. Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask any such provider what they claim and what of that value reaches you.