South Carolina Solar in 2026: The 25% State Credit & the Best Payback in the Batch

For most South Carolina homeowners, yes - and SC has the best economics in this batch of state guides. An 8 kW rooftop system costs about $22,400 (2.80/W - below the national average) and pays back in roughly 13 years, the fastest in the batch. Three things drive this: the best sun hours in the batch (5.1), the deepest incentive stack in the Southeast (a 25% state tax credit worth ~$4,900, plus 20-year property-tax and sales-tax exemptions), and a solid retail rate ($0.171/kWh). The 25-year ROI of approximately 163% is the highest in this batch. The complication is export policy - Act 62 (2019) moved SC from full-retail NEM to net billing - but the rich incentive stack more than offsets the reduced export credits.

South Carolina offers a state income tax credit of 25% of the system cost, capped at $3,500 per tax year, with carry-forward for up to 10 years. On a typical $22,400 8 kW system, the total credit is approximately $4,900 (the state-database value, reflecting 25% of the post-sales-tax effective basis). Most households spread this over 2 tax years because of the $3,500 annual cap. Crucially, unlike the federal Section 25D residential credit (which expired December 31, 2025), the SC state credit is <strong>still active in 2026</strong>. It is the swing factor that makes SC the best-payback state in this batch of comprehensive guides. The 10-year carry-forward means even households that cannot use the full $3,500 in a single tax year eventually capture the entire credit.

Act 62 (2019) is the South Carolina legislation that transitioned the state from full-retail net metering to a net-billing structure with reduced export credits. Under Act 62, exported surplus now earns a reduced credit - roughly ~$0.05-0.07/kWh depending on utility - rather than the full retail rate. Dominion Energy South Carolina, Duke Energy Carolinas/Progress, Santee Cooper, and the electric cooperatives each implement net billing with their own export-credit rate. Existing customers interconnected before the transition were generally grandfathered at their original terms. Act 62 is the reason SC's payback is not even faster than 13 years - but the rich incentive stack (the 25% state credit and the tax exemptions) more than offsets the reduced export value.

South Carolina runs effectively a two-tier system since Act 62 (2019). <strong>Tier 1 - Self-consumption:</strong> every kilowatt-hour you use on-site offsets the full retail purchase price ($0.15-0.18/kWh), entirely unaffected by Act 62. This is the economic backbone. <strong>Tier 2 - Net billing export:</strong> surplus exported to the grid earns a reduced credit, roughly ~$0.05-0.07/kWh depending on utility (the NemRate in our policy database is $0.06/kWh). This is roughly 3x less than the value of self-consumed energy. The lesson is the now-familiar one across net-billing states: size to consume, not to export. The 25% state credit counterweights the export penalty by lowering the effective project cost.

For most homeowners, a battery is a marginal-ROI purchase in South Carolina - not as clearly negative as in full-retail-NEM states, but rarely justified on economics alone. With net-billing exports already reduced under Act 62, a battery's incremental value comes from shifting consumption to avoid exporting at ~$0.05-0.07/kWh - which can be worth doing but rarely covers the battery's cost over its life, given that the 25% state credit does not apply to storage as favorably as to generation. Batteries in SC are most defensibly justified for <strong>resilience</strong>: hurricane season outages (the coast and Lowcountry are vulnerable to tropical systems), severe thunderstorm outages, and households with medical equipment dependencies. Coastal residents in particular get a stronger resilience case. Model the storage case explicitly with our <a href="/tools/battery-payback/">Battery Payback Calculator</a>.

A typical 8 kW rooftop system in South Carolina runs about $22,400 (2.80/W) before incentives - below the national average. The 30% federal residential credit (Section 25D) expired December 31, 2025, but South Carolina's 25% state income tax credit ($4,900 total on an 8 kW system, capped at $3,500/yr with 10-year carry-forward) is still active and is the swing factor. The 6% state sales tax (plus local) is exempt on solar equipment, saving roughly $1,350 at the point of sale. The 20-year property-tax exemption (SC Code 12-37-220) protects against reassessment on the added value. The combination of state credit + tax exemptions is what makes SC the best-payback state in this batch.

South Carolina has the deepest state-level incentive stack in this batch of comprehensive guides. The standout is the <strong>25% state income tax credit</strong> on system cost, capped at $3,500/yr with 10-year carry-forward - one of the most generous state credits in the Southeast. Layered on top are a <strong>20-year property-tax exemption</strong> (SC Code 12-37-220) and a <strong>sales-tax exemption</strong> (6% plus local). South Carolina has no SREC market for residential systems. The federal Section 25D residential credit expired December 31, 2025; leased/PPA systems may still access Section 48E for projects that began construction before July 4, 2026. The contrast with neighboring Tennessee (no state credit, no exemptions, no SREC market) is dramatic - the state credit is the structural difference.

South Carolina's investor-owned utilities and cooperatives divide the state. <strong>Dominion Energy South Carolina</strong> (formerly SCE&G) serves Columbia, Charleston, and the central midlands. <strong>Duke Energy Carolinas and Duke Energy Progress</strong> serve the Upstate (Greenville, Spartanburg) and the north-central tier (Rock Hill, Charlotte commuter corridor). <strong>Santee Cooper</strong> (South Carolina Public Service Authority) is the state-owned utility serving the Grand Strand (Myrtle Beach) directly and supplying 20 distribution cooperatives. The <strong>electric cooperatives</strong> serve significant rural territory. Check your electric bill to confirm your utility. Each implements Act 62 net billing with its own export-credit rate - so the value of your exports varies meaningfully by utility.

The 2026 expiration of the Section 25D residential credit sharpens the buy-versus-lease math, but South Carolina's 25% state credit means the buy case is materially stronger here than in thinnest-incentive states. A cash purchase or low-interest loan captures the full $4,900 state credit (spread over multiple tax years), the property-tax exemption, the sales-tax exemption, and the net-metering offset. A lease or PPA eliminates upfront cost and can still capture Section 48E (the developer claims the 30% federal credit and passes value through) on projects that began construction before July 4, 2026 - but read carefully whether the lease passes through the SC state credit or keeps it. Because the SC state credit is a meaningful amount of money, the buy-versus-lease decision in SC leans more toward purchase than in low-incentive states.

South Carolina averages about 5.1 peak sun hours per day - the best solar resource in this batch of comprehensive guides and one of the better 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 mountain foothills sit marginally lower. A south-facing 8 kW array tilted near latitude (~34°) typically produces on the order of $12,807 kWh per year (the state-database figure is 12,807 kWh) - the highest annual production in this batch. Hot, humid summers drive heavy air-conditioning load that aligns naturally with peak solar output, and mild winters keep shoulder-season production meaningful. Because Act 62 moved SC to net billing, the optimal strategy is to maximize self-consumption - size to your daytime cooling load rather than maximizing raw export.

There is a real argument for it - within reason. Because the SC state credit is 25% of system cost, a larger system generates a larger total credit (up to the cap structure). A 10 kW system at $28,000 generates a ~$7,000 state credit, vs the ~$4,900 credit on a $22,400 8 kW system. The catch is that the $3,500/yr cap means it takes longer to use up a larger credit - but the 10-year carry-forward gives plenty of runway for most tax-paying households. The other check on forward sizing is Act 62's net-billing structure: a larger system means more exported surplus at reduced rates, which can lengthen payback if the system is significantly oversized. The sweet spot is matching the array to your consumption with modest headroom - not maximizing raw system size for credit-capture alone.

It depends on your interconnection date. Systems interconnected before Act 62's transition (which phased in through 2021-2024) were generally grandfathered at full-retail export terms for a defined period. If you interconnected before the transition, check your interconnection paperwork or contact your utility to confirm your status. If you interconnected after the Act 62 transition, you are on the net-billing structure (Tier 2). Track your utility's current terms with our <a href="/tools/nem-grandfathering-calculator/">NEM Grandfathering Calculator</a>. The rich incentive stack (especially the still-active 25% state credit) means the case for new interconnections remains strong even on net billing - it just requires sizing to self-consumption rather than to export.