Solar in Washington: payback, sun by city and utility-scale capacity
Washington pays back in 21.6 years at $3.00 a watt (rank 51 of 51), 8.1 years longer than the middle state. 1,062 kWh per kW (rank 50) at 13.11 ¢ (rank 44 from the top): price of power drives it. Across 5 Washington cities, yearly output runs from 1,051 kWh per kW in Bellingham to 1,376 in Yakima. Jul is the best month at 149 kWh per kW and Dec the worst at 42. Utility-scale solar in Washington: 268 MW in 9 plants, 0.6% of 2025 generation; 1,650 MW more under construction or planned.
Washington: payback 21.6 years, rank 51 of 51
| Measure | Value | Rank of 51 | Median state |
|---|---|---|---|
| Output of 1 kW a year, kWh | 1,062 | 50 | 1,372 |
| Home price, ¢ per kWh | 13.11 | 44 | 15.37 |
| Value of 1 kW a year | $139 | 51 | $222 |
| Payback at $3.00 a watt | 21.6 years | 51 | 13.5 years |
EIA-861 (2024): 57,610 home net-metered systems in Washington, 17.1 per 1,000 accounts (rank 24), average 7.3 kW.
Sizes and prices per watt in Washington
| Washington kW | kWh a year | Value a year | Cost at $2.50 | At $3.00 | At $3.50 | t CO2 |
|---|---|---|---|---|---|---|
| 4 | 4,247 | $557 | $10,000 | $12,000 | $14,000 | 0.5 |
| 6 | 6,370 | $835 | $15,000 | $18,000 | $21,000 | 0.8 |
| 8 | 8,494 | $1,114 | $20,000 | $24,000 | $28,000 | 1.0 |
| 10 | 10,617 | $1,392 | $25,000 | $30,000 | $35,000 | 1.3 |
| 12 | 12,740 | $1,670 | $30,000 | $36,000 | $42,000 | 1.5 |
| Washington $ per watt | 100% retail | 75% | 50% | 25% |
|---|---|---|---|---|
| $2.00 | 14.4 | 19.2 | 28.7 | 57.5 |
| $2.50 | 18.0 | 23.9 | 35.9 | 71.8 |
| $3.00 | 21.6 | 28.7 | 43.1 | 86.2 |
| $3.50 | 25.1 | 33.5 | 50.3 | 100.6 |
| $4.00 | 28.7 | 38.3 | 57.5 | 115.0 |
Washington: 1,062 kWh/kW × 13.11 ¢ = 139 a year per kW; the 30% column (15.1 years at $3.00) is arithmetic only.
CSVSun inside Washington: 5 cities, 28% apart
| Washington city | kWh per kW a year | Against state point | Sun, kWh/m2 a day | Payback at $3.00 | Residents |
|---|---|---|---|---|---|
| Seattle | 1,088 | +2.5% | 3.95 | 21.0 | 741,440 |
| Spokane | 1,256 | +18.3% | 4.44 | 18.2 | 229,228 |
| Vancouver | 1,119 | +5.4% | 4.06 | 20.4 | 192,696 |
| Yakima | 1,376 | +29.6% | 4.91 | 16.6 | 96,810 |
| Bellingham | 1,051 | -1.0% | 3.83 | 21.8 | 92,367 |
Washington state point 47.32, -121.69; city points Seattle 47.62, -122.35; Spokane 47.67, -117.43; Vancouver 45.64, -122.60; Yakima 46.59, -120.55; Bellingham 48.75, -122.47. Panel and method: solar method.
Output by month in Washington cities: 12 rows
| Washington month | Seattle | Spokane | Vancouver | Yakima | Bellingham |
|---|---|---|---|---|---|
| Jan | 39.7 | 40.1 | 32.5 | 44.1 | 28.0 |
| Feb | 54.8 | 63.2 | 60.7 | 77.7 | 51.3 |
| Mar | 81.6 | 99.2 | 86.2 | 118.8 | 76.9 |
| Apr | 115.7 | 131.2 | 113.2 | 146.1 | 112.9 |
| May | 137.5 | 148.3 | 131.9 | 158.6 | 131.5 |
| Jun | 131.0 | 142.9 | 132.0 | 165.7 | 128.1 |
| Jul | 143.4 | 176.6 | 155.5 | 179.6 | 151.6 |
| Aug | 142.4 | 156.0 | 142.2 | 158.1 | 135.0 |
| Sep | 102.2 | 125.3 | 114.2 | 131.7 | 99.5 |
| Oct | 68.3 | 88.6 | 71.7 | 100.9 | 68.2 |
| Nov | 38.3 | 46.3 | 46.3 | 53.2 | 37.0 |
| Dec | 33.1 | 38.9 | 32.7 | 41.3 | 30.7 |
Washington: 5 cities, best month 180 and worst 28 kWh per kW across them.
CSVBest and worst month in Washington: Jul 149, Dec 42 kWh per kW
| Washington month | kWh per kW | Price ¢ | Value per kW | kWh per kW per sun unit |
|---|---|---|---|---|
| Jan | 47.3 | 11.78 | $5.57 | 0.81 |
| Feb | 59.3 | 12.47 | $7.39 | 0.80 |
| Mar | 78.1 | 12.62 | $9.86 | 0.79 |
| Apr | 101.1 | 13.02 | $13.16 | 0.77 |
| May | 111.1 | 13.65 | $15.17 | 0.75 |
| Jun | 114.8 | 12.96 | $14.88 | 0.74 |
| Jul | 148.9 | 13.45 | $20.03 | 0.73 |
| Aug | 142.5 | 13.64 | $19.44 | 0.73 |
| Sep | 99.0 | 13.79 | $13.65 | 0.75 |
| Oct | 73.8 | 14.06 | $10.38 | 0.78 |
| Nov | 44.0 | 13.85 | $6.09 | 0.81 |
| Dec | 41.8 | 13.33 | $5.57 | 0.82 |
Washington: December to February give 14% of a year (rank 4 of 51, 1 = most winter); the best month is 3.6 times the worst. Output per unit of sun is highest in Dec (0.82) and lowest in Jul (0.73); 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 Washington is not modelled separately.
Utility-scale solar in Washington: 268 MW
Washington: 268 MW of operable utility-scale solar in 9 plants across 6 counties (EIA-860, 2025), rank 40 of 51; 35 W per resident, rank 48. Solar made 0.6% of Washington's net generation in 2025 (EIA-923), rank 47, -6.2 points against the national share. Biggest plants: Lund Hill Solar in Klickitat County, 150 MW (2022); Goose Prairie Solar in Yakima County, 80 MW (2024); Adams Nielson Solar in Adams County, 19 MW (2018). By county: Klickitat 150 MW, Yakima 80 MW, Adams 19 MW, Kittitas 16 MW. Proposed: 130 MW under construction (1 plant) and 1,520 MW planned (7 plants); batteries 4 MW running and 1,655 MW proposed.
| Washington year | MW added | Cumulative share of today's MW |
|---|---|---|
| 2019 | 0 | 0% |
| 2020 | 3 | 1% |
| 2021 | 0 | 1% |
| 2022 | 165 | 63% |
| 2023 | 0 | 63% |
| 2024 | 80 | 93% |
| 2025 | 0 | 93% |
Net metering and CO2 in Washington
EIA-861 (2024): 57,610 home net-metered systems in Washington, 17.1 per 1,000 accounts (rank 24), average 7.3 kW.
6 kW in Washington: 6,370 kWh a year displaces 0.8 t CO2 at 0.120 kg per kWh, -2.3 t against the average state.
Washington utilities and solar payback
| Washington utility | Homes | Price ¢ | Value of 1 kW | Payback at $3.00 |
|---|---|---|---|---|
| Puget Sound Energy Inc | 1,091,599 | 14.63 | $155 | 19.3 yr |
| City of Seattle | 459,964 | 14.09 | $150 | 20.1 yr |
| PUD No 1 of Snohomish County | 346,532 | 11.51 | $122 | 24.5 yr |
| Avista Corp | 246,055 | 11.87 | $126 | 23.8 yr |
| PUD No 1 of Clark County | 219,477 | 10.41 | $111 | 27.1 yr |
| City of Tacoma | 180,357 | 10.81 | $115 | 26.1 yr |
| PUD No 1 of Benton County | 50,072 | 8.81 | $94 | 32.1 yr |
| PUD No 1 of Cowlitz County | 48,267 | 8.80 | $93 | 32.1 yr |
| PUD No 2 of Grant County | 42,485 | 6.01 | $64 | 47.0 yr |
| PUD No 1 of Chelan County | 42,120 | 3.67 | $39 | 77.0 yr |
| Inland Power & Light Company | 41,684 | 8.98 | $95 | 31.5 yr |
| PUD No 1 of Grays Harbor County | 39,881 | 12.52 | $133 | 22.6 yr |
Washington among its neighbours
| Closest to Washington | Payback, years | kWh per kW | Price, ¢ | Utility-scale solar, points of generation | Miles away |
|---|---|---|---|---|---|
| Washington (this page) | 21.6 | 1,062 | 13.11 | 0.6 | - |
| Oregon | -4.3 | +68 | +2.26 | +3.5 | 178 |
| Idaho | -3.0 | +309 | -1.29 | +7.4 | 376 |
| Montana | -4.0 | +254 | -0.13 | +0.7 | 493 |
| Utah | -6.7 | +479 | -0.04 | +16.7 | 679 |
Washington against its neighbours in the payback ranking
- -1 places, Idaho -3.0 years against Washington
- +0 places, North Dakota -2.4 years against Washington
- Washington, rank 51: 21.6 years
Your numbers for Washington
Limits in Washington
Washington: with the old 30% credit (IRS, ended 2025) payback would be 15.1 years instead of 21.6, so the calculator starts at 0%. No Washington export rates in our data: output counts at 13.11 ¢. All limits.
Sources for Washington
- PVWatts v8 (NLR), 5 Washington cities and one state point: 1,062 kWh per kW
- EIA-860 2025 and EIA-923 2025: 268 MW of solar in Washington
- EIA-861 2024: 57,610 net-metered systems in Washington
- EIA retail sales 2025: 13.11 ¢ per kWh in Washington
- IRS 25D (ended 2025): 15.1 years in Washington with it; licences and periods for Washington
More about Washington
Washington electricity hub, Washington EV charging: 3,163 stations, where Washington ranks for rooftop solar, 21.6 years against 51 states, Washington calculators.
Questions
Solar payback in Washington?
21.6 years at $3.00 a watt; 18.0 at $2.50; 25.1 at $3.50; 1,062 kWh per kW at 13.11 ¢.
Washington sunshine for solar panels?
1,062 kWh per kW a year at the state point, rank 50 of 51; from 1,051 in Bellingham to 1,376 in Yakima.
Winter cut in Washington solar output?
December to February give 14% of the year; Jul makes 149 kWh per kW and Dec 42.
Washington utility-scale solar capacity?
268 MW in 9 plants (EIA-860), 35 W per resident, rank 48; 1,650 MW proposed.
Where in Washington is solar best?
Yes: 28% between Bellingham and Yakima in yearly output.
Washington electricity from solar, what share?
0.6% of 2025 net generation, rank 47 of 51, -6.2 points against the nation.
Net metering in Washington?
57,610 systems, 17.1 per 1,000 accounts, rank 24.
Washington pays half price for exports?
Payback 43.1 years at a 50% retail share.
CO2 displaced in Washington?
0.8 t a year on 6 kW at 0.120 kg per kWh.
Federal solar credit in Washington: still available?
Ended 2025 (IRS 25D); with it Washington payback would be 15.1 years, not 21.6.