South Dakota pays about 12.7¢ per kilowatt-hour for residential electricity and receives about 4.7 kWh per square metre per day of sunlight — 41st and 22nd respectively among the 50 states and DC tracked here. Those two numbers set the ceiling on what rooftop solar returns in South Dakota, and they point in opposite directions.
Where South Dakota sits against the rest of the country
South Dakota is 2.1¢/kWh below the median residential rate across this dataset (14.8¢/kWh) and 0.1 kWh/m²/day above the median insolation (4.6 kWh/m²/day). Under this site's standard assumptions, that combination puts South Dakota 44th of 51 for modeled payback speed, at 15.6 years against a dataset median of 13.5 years.
What actually drives payback in South Dakota
South Dakota is sunlight-led: 22nd for insolation but only 41st for electricity price. Swap South Dakota's sunlight for the dataset median and payback moves to 15.9 years (0.3 years of swing). Swap its electricity rate instead and payback moves to 13.8 years (1.9 years of swing). The rate swap is the larger of the two, so what a kilowatt-hour costs is the input deciding the outcome in South Dakota.
State incentives on record
Recorded for South Dakota: No statewide net metering mandate; property tax discount; case-by-case interconnection.
No federal credit is applied above (Section 25D expired 31 December 2025), and export terms often matter more than the headline rate (net metering guide).
The modeled system, in numbers
At South Dakota's sunlight level a 7 kW array produces roughly 9,367 kWh a year, worth about $1,190 in first-year bill savings at 12.7¢/kWh against an assumed $22,400 installed cost. A ten-year payback at this sunlight level would require a residential rate of about 21.4¢/kWh, which is 8.7¢ above what South Dakota households pay today.
States with comparable economics
South Dakota's closest analogues by modeled payback are Tennessee (15.5 years), Nebraska (15.8 years), Kentucky (15.9 years). They arrive there from different rate and sunlight combinations, so their incentive rows are the useful comparison.