Solar in Idaho: payback, sun by city and utility-scale capacity
Idaho pays back in 18.5 years at $3.00 a watt (rank 49 of 51), 5.0 years longer than the middle state. 1,371 kWh per kW (rank 27) at 11.82 ¢ (rank 50 from the top): sunshine drives it. Across 5 Idaho cities, yearly output runs from 1,183 kWh per kW in Coeur d'Alene to 1,521 in Twin Falls. Jul is the best month at 165 kWh per kW and Dec the worst at 64. Utility-scale solar in Idaho: 702 MW in 13 plants, 8.0% of 2025 generation; 625 MW more under construction or planned.
Idaho: payback 18.5 years, rank 49 of 51
| Measure | Value | Rank of 51 | Median state |
|---|---|---|---|
| Output of 1 kW a year, kWh | 1,371 | 27 | 1,372 |
| Home price, ¢ per kWh | 11.82 | 50 | 15.37 |
| Value of 1 kW a year | $162 | 49 | $222 |
| Payback at $3.00 a watt | 18.5 years | 49 | 13.5 years |
EIA-861 (2024): 18,969 home net-metered systems in Idaho, 21.9 per 1,000 accounts (rank 19), average 7.7 kW.
Idaho utilities and solar payback
| Idaho utility | Homes | Price ¢ | Value of 1 kW | Payback at $3.00 |
|---|---|---|---|---|
| Idaho Power Co | 525,751 | 11.76 | $161 | 18.6 yr |
| Kootenai Electric Cooperative | 30,378 | 12.21 | $167 | 17.9 yr |
| City of Idaho Falls | 28,142 | 9.25 | $127 | 23.7 yr |
| Northern Lights, Inc | 18,511 | 11.49 | $158 | 19.0 yr |
| Fall River Rural Elec Coop Inc | 15,433 | 11.11 | $152 | 19.7 yr |
| United Electric Co-op, Inc | 5,100 | 7.89 | $108 | 27.7 yr |
Sizes and prices per watt in Idaho
| Idaho kW | kWh a year | Value a year | Cost at $2.50 | At $3.00 | At $3.50 | t CO2 |
|---|---|---|---|---|---|---|
| 4 | 5,484 | $648 | $10,000 | $12,000 | $14,000 | 0.8 |
| 6 | 8,225 | $972 | $15,000 | $18,000 | $21,000 | 1.2 |
| 8 | 10,967 | $1,296 | $20,000 | $24,000 | $28,000 | 1.6 |
| 10 | 13,709 | $1,620 | $25,000 | $30,000 | $35,000 | 1.9 |
| 12 | 16,451 | $1,944 | $30,000 | $36,000 | $42,000 | 2.3 |
| Idaho $ per watt | 100% retail | 75% | 50% | 25% |
|---|---|---|---|---|
| $2.00 | 12.3 | 16.5 | 24.7 | 49.4 |
| $2.50 | 15.4 | 20.6 | 30.9 | 61.7 |
| $3.00 | 18.5 | 24.7 | 37.0 | 74.1 |
| $3.50 | 21.6 | 28.8 | 43.2 | 86.4 |
| $4.00 | 24.7 | 32.9 | 49.4 | 98.7 |
Idaho: 1,371 kWh/kW × 11.82 ¢ = 162 a year per kW; the 30% column (13.0 years at $3.00) is arithmetic only.
CSVNet metering and CO2 in Idaho
EIA-861 (2024): 18,969 home net-metered systems in Idaho, 21.9 per 1,000 accounts (rank 19), average 7.7 kW.
6 kW in Idaho: 8,225 kWh a year displaces 1.2 t CO2 at 0.142 kg per kWh, -1.9 t against the average state.
Sun inside Idaho: 5 cities, 24% apart
| Idaho city | kWh per kW a year | Against state point | Sun, kWh/m2 a day | Payback at $3.00 | Residents |
|---|---|---|---|---|---|
| Boise City | 1,468 | +7.1% | 5.22 | 17.3 | 235,701 |
| Idaho Falls | 1,450 | +5.8% | 5.10 | 17.5 | 66,672 |
| Pocatello | 1,472 | +7.4% | 5.20 | 17.2 | 57,152 |
| Coeur d'Alene | 1,183 | -13.7% | 4.26 | 21.4 | 55,558 |
| Twin Falls | 1,521 | +11.0% | 5.39 | 16.7 | 53,219 |
Idaho state point 44.14, -115.35; city points Boise City 43.60, -116.23; Idaho Falls 43.49, -112.04; Pocatello 42.87, -112.46; Coeur d'Alene 47.70, -116.79; Twin Falls 42.56, -114.46. Panel and method: solar method.
Output by month in Idaho cities: 12 rows
| Idaho month | Boise City | Idaho Falls | Pocatello | Coeur d'Alene | Twin Falls |
|---|---|---|---|---|---|
| Jan | 56.9 | 50.9 | 68.5 | 42.2 | 71.0 |
| Feb | 81.0 | 74.9 | 87.0 | 54.8 | 88.2 |
| Mar | 108.9 | 125.7 | 125.3 | 91.4 | 126.3 |
| Apr | 152.0 | 141.2 | 147.9 | 116.3 | 152.0 |
| May | 162.5 | 158.2 | 158.2 | 139.3 | 173.9 |
| Jun | 171.2 | 168.2 | 167.7 | 143.7 | 175.4 |
| Jul | 179.3 | 182.3 | 176.4 | 167.2 | 174.0 |
| Aug | 169.6 | 165.7 | 160.6 | 151.1 | 161.8 |
| Sep | 144.5 | 137.7 | 138.7 | 115.8 | 137.3 |
| Oct | 117.5 | 116.8 | 116.0 | 82.8 | 118.0 |
| Nov | 70.0 | 79.2 | 71.2 | 43.5 | 79.8 |
| Dec | 54.9 | 49.2 | 54.5 | 35.2 | 63.4 |
Idaho: 5 cities, best month 182 and worst 35 kWh per kW across them.
CSVBest and worst month in Idaho: Jul 165, Dec 64 kWh per kW
| Idaho month | kWh per kW | Price ¢ | Value per kW | kWh per kW per sun unit |
|---|---|---|---|---|
| Jan | 64.3 | 10.82 | $6.96 | 0.84 |
| Feb | 79.6 | 10.95 | $8.72 | 0.82 |
| Mar | 118.2 | 11.57 | $13.68 | 0.81 |
| Apr | 136.9 | 11.89 | $16.28 | 0.79 |
| May | 146.5 | 11.88 | $17.40 | 0.76 |
| Jun | 152.6 | 12.07 | $18.42 | 0.74 |
| Jul | 165.4 | 12.28 | $20.31 | 0.72 |
| Aug | 146.5 | 12.08 | $17.70 | 0.73 |
| Sep | 130.7 | 12.50 | $16.34 | 0.76 |
| Oct | 96.9 | 12.46 | $12.07 | 0.79 |
| Nov | 69.5 | 12.25 | $8.51 | 0.83 |
| Dec | 63.7 | 11.87 | $7.56 | 0.84 |
Idaho: December to February give 15% of a year (rank 8 of 51, 1 = most winter); the best month is 2.6 times the worst. Output per unit of sun is highest in Dec (0.84) and lowest in Jul (0.72); PVWatts lowers cell output when the panel is hot, and the sun angle changes with the season. Our runs use one fixed 14% loss figure for every place, so snow or soiling in Idaho is not modelled separately.
Utility-scale solar in Idaho: 702 MW
Idaho: 702 MW of operable utility-scale solar in 13 plants across 5 counties (EIA-860, 2025), rank 33 of 51; 371 W per resident, rank 22. Solar made 8.0% of Idaho's net generation in 2025 (EIA-923), rank 16, +1.2 points against the national share. Biggest plants: Matrix Pleasant Valley in Ada County, 200 MW (2025); Jackpot Solar, LLC in Twin Falls County, 120 MW (2022); Franklin Solar Hybrid in Twin Falls County, 100 MW (2024). By county: Ada 260 MW, Twin Falls 222 MW, Elmore 160 MW, Power 40 MW. Proposed: 125 MW under construction (1 plant) and 500 MW planned (2 plants); batteries 459 MW running and 300 MW proposed.
| Idaho year | MW added | Cumulative share of today's MW |
|---|---|---|
| 2019 | 2 | 0% |
| 2020 | 0 | 0% |
| 2021 | 0 | 0% |
| 2022 | 120 | 17% |
| 2023 | 40 | 23% |
| 2024 | 100 | 37% |
| 2025 | 200 | 66% |
Idaho among its neighbours
| Closest to Idaho | Payback, years | kWh per kW | Price, ¢ | Utility-scale solar, points of generation | Miles away |
|---|---|---|---|---|---|
| Idaho (this page) | 18.5 | 1,371 | 11.82 | 8.0 | - |
| Montana | -0.9 | -55 | +1.16 | -6.7 | 267 |
| Utah | -3.6 | +170 | +1.25 | +9.3 | 311 |
| Oregon | -1.2 | -241 | +3.55 | -3.9 | 361 |
| Washington | +3.0 | -309 | +1.29 | -7.4 | 376 |
Idaho against its neighbours in the payback ranking
- -1 places, Oregon -1.2 years against Idaho
- +0 places, Montana -0.9 years against Idaho
- Idaho, rank 49: 18.5 years
- +2 places, North Dakota +0.6 years against Idaho
- +3 places, Washington +3.0 years against Idaho
Your numbers for Idaho
Limits in Idaho
Idaho: with the old 30% credit (IRS, ended 2025) payback would be 13.0 years instead of 18.5, so the calculator starts at 0%. No Idaho export rates in our data: output counts at 11.82 ¢. All limits.
Sources for Idaho
- PVWatts v8 (NLR), 5 Idaho cities and one state point: 1,371 kWh per kW
- EIA-860 2025 and EIA-923 2025: 702 MW of solar in Idaho
- EIA-861 2024: 18,969 net-metered systems in Idaho
- EIA retail sales 2025: 11.82 ¢ per kWh in Idaho
- IRS 25D (ended 2025): 13.0 years in Idaho with it; licences and periods for Idaho
More about Idaho
Idaho electricity hub, Idaho EV charging: 257 stations, where Idaho ranks for rooftop solar, 18.5 years against 51 states, Idaho calculators.
Questions
Solar payback in Idaho?
18.5 years at $3.00 a watt; 15.4 at $2.50; 21.6 at $3.50; 1,371 kWh per kW at 11.82 ¢.
Where in Idaho is solar best?
Yes: 24% between Coeur d'Alene and Twin Falls in yearly output.
Winter cut in Idaho solar output?
December to February give 15% of the year; Jul makes 165 kWh per kW and Dec 64.
Idaho electricity from solar, what share?
8.0% of 2025 net generation, rank 16 of 51, +1.2 points against the nation.
Net metering in Idaho?
18,969 systems, 21.9 per 1,000 accounts, rank 19.
Idaho utility-scale solar capacity?
702 MW in 13 plants (EIA-860), 371 W per resident, rank 22; 625 MW proposed.
Idaho sunshine for solar panels?
1,371 kWh per kW a year at the state point, rank 27 of 51; from 1,183 in Coeur d'Alene to 1,521 in Twin Falls.
Idaho pays half price for exports?
Payback 37.0 years at a 50% retail share.
CO2 displaced in Idaho?
1.2 t a year on 6 kW at 0.142 kg per kWh.
Federal solar credit in Idaho: still available?
Ended 2025 (IRS 25D); with it Idaho payback would be 13.0 years, not 18.5.