Solar in South Carolina

South Carolina's residential solar policy was reshaped by Act 62 (2021), which transitioned the state from full retail net metering to a net-billing structure with reduced export credits. Dominion Energy South Carolina (formerly SCE&G), Duke Energy Carolinas/Progress, Santee Cooper, and the electric cooperatives each implement the net-billing structure with their own export-credit terms. Existing customers are generally grandfathered at the terms of their interconnection.

The standout state incentive is the South Carolina solar tax credit: 25% of system cost capped at $3,500 per year, with carry-forward for up to 10 years — one of the most generous state credits in the Southeast. The state also offers a 20-year property tax exemption (SC Code 12-37-220) and a sales tax exemption (6% plus local). There is no SREC market for residential systems. The federal Section 25D residential credit expired December 31, 2025; leased and PPA systems may still access Section 48E for projects that began construction before July 6, 2026.

The policy direction has been supportive on incentives but has tracked the regional shift toward reduced export compensation. The combination of the generous state credit, the tax exemptions, and the still-decent retail rate keeps the South Carolina case strong for households that size for self-consumption. The net-billing export rate is the key variable to confirm at installation.

South Carolina's 5.1 peak sun hours give it one of the better solar resources on the East Coast. The coastal plain (Charleston, Myrtle Beach, the Lowcountry) runs above the state average, while the Upstate (Greenville, Spartanburg) and the western mountains sit marginally lower. Hot, humid summers drive heavy air-conditioning load that aligns naturally with peak solar output, and winters are mild enough that shoulder-season production remains meaningful, giving South Carolina a flatter annual curve than northern states.

Because Act 62 moved the state to net billing with reduced export credits, the design philosophy favors self-consumption. A system matched to daytime household load — particularly afternoon air-conditioning — captures the full ~$0.15/kWh retail value of every panel, while an oversized array exporting a large midday surplus earns back only the reduced credit. West- and southwest-facing arrays that extend production into the late-afternoon cooling peak can outperform pure south-facing designs on dollars.

The 25% state tax credit reinforces a maximize-output approach indirectly, since a larger system generates a larger credit (up to the $3,500 annual cap, carried forward up to 10 years). The installer's familiarity with the specific utility's net-billing export rate — Dominion, Duke, Santee Cooper, or the local cooperative — is the detail that most affects a correct sizing decision.

South Carolina's $2.80/W installed cost is below the national average, with a typical 8 kW system around $22,400 before incentives. The standout offset is the 25% state income tax credit (capped at $3,500 per year, carry-forward for 10 years), which directly reduces the effective project price over time — a particularly valuable lever now that the 30% federal residential credit (Section 25D) ended December 31, 2025. The 20-year property tax exemption (SC Code 12-37-220) and the sales tax exemption (6% plus local) are automatic.

Payback near 13.0 years on the 8 kW model is solid for the Southeast, driven by the combination of low cost, abundant sun, and the deep state incentive stack. The self-consumed portion of production earns the full ~$0.15/kWh retail rate; the exported surplus earns the reduced net-billing credit, which is why oversized systems pay back more slowly. Households that capture the full state credit (spread over multiple tax years via carry-forward) see the fastest payback.

South Carolina offers no SREC market, so the state credit and the tax exemptions are the structural offsets. Leased and PPA systems may access the federal Section 48E credit (through July 6, 2026) in addition. The state credit's carry-forward structure means its full value accrues even for households that cannot use the entire $3,500 in a single tax year.