What this means for a South Dakota household
Over the last 12 months the average price was 14.20¢ per kWh and the average home used 987 kWh a month, so a typical South Dakota household spent about $140 a month on electricity, or $1,682 a year. Use is 13% above the US average of 870 kWh a month, peaking in January at 1,269 kWh.
Driving a Tesla Model Y Long Range AWD 1,000 miles a month takes 275 kWh from the wall (EPA 27.5 kWh/100 mi), about $39 at the state average. A 25.5 mpg gasoline car covering the same distance at $3.89 a gallon (Midwest (PADD 2) average, August 2026) costs about $153.
The state average hides the real spread. Utilities in the same state charge different prices, and on a time-of-use plan the same kWh costs more in the peak hours than off-peak; each utility page shows by how much. Open NorthWestern Energy’s page to see its periods and fixed charge, or run the calculators below with South Dakota preloaded.
Natural gas for homes averaged $0.99 per therm over the 12 months to June 2026 (EIA, all charges included), and a typical gas-heated home uses about 561 therms a year for heating. The heat pump calculator compares that with electric heating on your plan.
A south-facing, 20° rooftop array in South Dakota produces about 1,421 kWh per installed kW a year (NREL PVWatts at the state’s population centre). What that is worth depends on your utility’s export rule, shown on each utility’s page.