Solar panels in Rapid City, SD
Roofs in Rapid City get about 1,734 hours of usable sunlight a year — more than 71% of the cities we've measured. Here's what that means in cost, savings and payback, using real rooftop data rather than a national average.
Check your specific roof in Rapid City → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Rapid City solar system costs
A 19-panel system (7.6 kW) is about right for an average Rapid City home using 10,800 kWh a year. It would produce roughly 11,202 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 4,716 | $6,384 | $580 | 11 yrs |
| 12 panels | 4.8 kW | 7,075 | $9,576 | $870 | 11 yrs |
| 16 panels | 6.4 kW | 9,433 | $12,768 | $1,160 | 11 yrs |
| 20 panels | 8 kW | 11,791 | $15,960 | $1,359 | 11.7 yrs |
| 26 panels | 10.4 kW | 15,329 | $20,748 | $1,468 | 14.1 yrs |
Notice that payback barely improves as systems get bigger, and eventually gets worse. That's because you can only save money on electricity you were going to buy anyway. Once a system covers your usage, extra panels mostly generate exports at a much lower rate.
Why Rapid City gets 1,734 sun hours
That figure comes from Google's analysis of real rooftops across Rapid City — it already accounts for shading from trees, chimneys and neighbouring buildings, which is why it's lower than the raw "hours of daylight" figures you'll see elsewhere. An unusually open, unshaded roof in Rapid City reaches about 1,745 hours, roughly 1% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,734 hrs/yr |
|---|---|
| Unshaded roof | 1,745 hrs/yr |
| Electricity rate (South Dakota avg) | 12.3¢/kWh |
| Installed cost assumed | $2.85/W |
| Panel size assumed | 400 W |
| Federal tax credit | 30% |
| Typical household usage | 10,800 kWh/yr |
| Power used as generated | 34% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 8 |
| Google imagery from | 2012 |
Nearby cities
See all of South Dakota → statewide sunlight, rates, incentives and every city we've measured.
Rapid City solar questions
How many solar panels do I need in Rapid City?
About 19 panels for an average home. Rapid City roofs get 1,734 usable sun hours a year, so each 400W panel produces roughly 590 kWh annually.
Is solar worth it in Rapid City?
At 12.3¢/kWh and 1,734 sun hours, a typical system pays for itself in about 11.3 years and returns roughly $18,357 over 25 years. That is slower than the national average, so compare quotes carefully.
How much do solar panels cost in Rapid City?
A 7.6 kW system costs about $21,660 before incentives and $15,162 after the 30% federal tax credit. Prices vary by installer, roof complexity and equipment.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average South Dakota electricity rates. Not a quote and not financial advice. Your roof, usage, utility plan and local incentives will change these numbers — get real quotes before buying.