In South Dakota, a 8.4-kW system for an average home costs about $21,485 after incentives in 2026, saves about $1,722 in the first year and pays back in 11 years.
| Item | Amount |
|---|---|
| Solar, 8.36 kW × $2.57/W | $21,485 |
| Federal credit (0%) | $0 |
| Net cost | $21,485 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $21,485 | $1,722 | 11 yr | $37,550 |
| Rates rise 5.6%/yr (2020–25 pace) | $21,485 | $1,722 | 9.9 yr | $61,422 |
| Rates stay flat | $21,485 | $1,722 | 12.8 yr | $19,302 |
| Survey price $3.6/W (LBNL) | $30,096 | $1,722 | 14.6 yr | $28,940 |
| Add 13.5-kWh battery | $33,824 | $1,722 | 16.1 yr | $25,211 |
| Exports cut to 50% of retail | $15,831 | $893 | 14.9 yr | $14,625 |
Verdict: at average South Dakota numbers, solar is a solid investment in 2026 — payback takes 11 years, leaving you $37,550 ahead after 25 years. Pay cash if you can: Berkeley Lab found loan-financed systems priced about $1.50/W above cash installs in 2025, which can add years to the payback.
Net metering and exports in South Dakota: Not verified for this page — check your utility's net metering or export-credit tariff before you sign. The calculator assumes 1:1 kWh net metering (the best case).
Battery: a 13.5-kWh battery at the South Dakota average of $914/kWh adds $12,339 and saves almost nothing extra under 1:1 net metering — buy it for backup, not payback; payback becomes 16.1 years.
Lease or PPA instead? The owner can still claim the 30% 48E credit if construction began by July 4, 2026 or the system is in service by Dec 31, 2027 — ask whether that discount is in the monthly price.
The full method, material data and tips are on the main solar payback calculator page.