Solar in California: payback, sun by city and utility-scale capacity
California pays back in 5.5 years at $3.00 a watt (rank 2 of 51), 8.0 years shorter than the middle state. 1,687 kWh per kW (rank 5) at 32.54 ¢ (rank 2 from the top): sun and price equally drives it. Across 5 California cities, yearly output runs from 1,430 kWh per kW in San Francisco to 1,682 in San Diego. May is the best month at 178 kWh per kW and Jan the worst at 83. Utility-scale solar in California: 24,831 MW in 946 plants, 26.8% of 2025 generation; 8,606 MW more under construction or planned.
California: payback 5.5 years, rank 2 of 51
| Measure | Value | Rank of 51 | Median state |
|---|---|---|---|
| Output of 1 kW a year, kWh | 1,687 | 5 | 1,372 |
| Home price, ¢ per kWh | 32.54 | 2 | 15.37 |
| Value of 1 kW a year | $549 | 2 | $222 |
| Payback at $3.00 a watt | 5.5 years | 2 | 13.5 years |
EIA-861 (2024): 2,099,871 home net-metered systems in California, 147.7 per 1,000 accounts (rank 2), average 6.1 kW.
Sizes and prices per watt in California
| California kW | kWh a year | Value a year | Cost at $2.50 | At $3.00 | At $3.50 | t CO2 |
|---|---|---|---|---|---|---|
| 4 | 6,748 | $2,196 | $10,000 | $12,000 | $14,000 | 1.2 |
| 6 | 10,123 | $3,294 | $15,000 | $18,000 | $21,000 | 1.8 |
| 8 | 13,497 | $4,392 | $20,000 | $24,000 | $28,000 | 2.4 |
| 10 | 16,871 | $5,490 | $25,000 | $30,000 | $35,000 | 3.0 |
| 12 | 20,245 | $6,588 | $30,000 | $36,000 | $42,000 | 3.6 |
| California $ per watt | 100% retail | 75% | 50% | 25% |
|---|---|---|---|---|
| $2.00 | 3.6 | 4.9 | 7.3 | 14.6 |
| $2.50 | 4.6 | 6.1 | 9.1 | 18.2 |
| $3.00 | 5.5 | 7.3 | 10.9 | 21.9 |
| $3.50 | 6.4 | 8.5 | 12.8 | 25.5 |
| $4.00 | 7.3 | 9.7 | 14.6 | 29.1 |
California: 1,687 kWh/kW × 32.54 ¢ = 549 a year per kW; the 30% column (3.8 years at $3.00) is arithmetic only.
CSVSun inside California: 5 cities, 16% apart
| California city | kWh per kW a year | Against state point | Sun, kWh/m2 a day | Payback at $3.00 | Residents |
|---|---|---|---|---|---|
| Los Angeles | 1,679 | -0.5% | 6.10 | 5.5 | 3,857,897 |
| San Diego | 1,682 | -0.3% | 6.05 | 5.5 | 1,385,061 |
| San Jose | 1,624 | -3.7% | 5.86 | 5.7 | 990,054 |
| San Francisco | 1,430 | -15.2% | 4.93 | 6.4 | 836,321 |
| Fresno | 1,654 | -1.9% | 6.05 | 5.6 | 543,615 |
California state point 35.42, -119.37; city points Los Angeles 34.02, -118.41; San Diego 32.81, -117.14; San Jose 37.30, -121.81; San Francisco 37.73, -123.03; Fresno 36.78, -119.79. Panel and method: solar method.
Output by month in California cities: 12 rows
| California month | Los Angeles | San Diego | San Jose | San Francisco | Fresno |
|---|---|---|---|---|---|
| Jan | 108.5 | 116.2 | 79.5 | 85.2 | 74.7 |
| Feb | 110.3 | 110.9 | 86.9 | 94.9 | 101.8 |
| Mar | 144.7 | 142.7 | 141.0 | 130.1 | 140.6 |
| Apr | 156.1 | 155.9 | 147.5 | 146.6 | 152.6 |
| May | 165.1 | 149.8 | 168.9 | 163.6 | 177.0 |
| Jun | 162.3 | 161.6 | 172.8 | 153.3 | 180.1 |
| Jul | 168.5 | 169.6 | 185.3 | 125.6 | 178.5 |
| Aug | 168.3 | 167.8 | 177.1 | 129.2 | 173.3 |
| Sep | 142.5 | 142.1 | 150.0 | 121.1 | 153.7 |
| Oct | 135.4 | 137.6 | 134.8 | 115.7 | 134.3 |
| Nov | 116.0 | 113.6 | 95.5 | 89.5 | 105.4 |
| Dec | 101.5 | 114.7 | 85.0 | 75.5 | 82.3 |
California: 5 cities, best month 185 and worst 75 kWh per kW across them.
CSVBest and worst month in California: May 178, Jan 83 kWh per kW
| California month | kWh per kW | Price ¢ | Value per kW | kWh per kW per sun unit |
|---|---|---|---|---|
| Jan | 82.9 | 30.28 | $25.10 | 0.80 |
| Feb | 105.2 | 31.72 | $33.37 | 0.78 |
| Mar | 142.6 | 32.48 | $46.32 | 0.77 |
| Apr | 161.6 | 33.82 | $54.65 | 0.77 |
| May | 178.1 | 33.29 | $59.29 | 0.76 |
| Jun | 176.9 | 33.59 | $59.42 | 0.75 |
| Jul | 175.1 | 32.66 | $57.19 | 0.74 |
| Aug | 170.6 | 31.65 | $53.99 | 0.74 |
| Sep | 157.3 | 32.04 | $50.40 | 0.74 |
| Oct | 139.7 | 33.60 | $46.94 | 0.76 |
| Nov | 105.4 | 31.89 | $33.61 | 0.78 |
| Dec | 91.8 | 34.71 | $31.86 | 0.80 |
California: December to February give 17% of a year (rank 16 of 51, 1 = most winter); the best month is 2.1 times the worst. Output per unit of sun is highest in Dec (0.80) and lowest in Aug (0.74); 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 California is not modelled separately.
Utility-scale solar in California: 24,831 MW
California: 24,831 MW of operable utility-scale solar in 946 plants across 44 counties (EIA-860, 2025), rank 2 of 51; 633 W per resident, rank 10. Solar made 26.8% of California's net generation in 2025 (EIA-923), rank 2, +20.0 points against the national share. Biggest plants: Topaz Solar Farm in San Luis Obispo County, 586 MW (2014); Bellefield Solar and Energy Storage Farm in Kern County, 500 MW (2025); Solar Star 1 in Kern County, 318 MW (2015). By county: Kern 6,612 MW, Riverside 4,746 MW, San Bernardino 2,390 MW, Imperial 2,156 MW. Proposed: 3,394 MW under construction (93 plants) and 5,212 MW planned (32 plants); batteries 14,924 MW running and 11,439 MW proposed.
| California year | MW added | Cumulative share of today's MW |
|---|---|---|
| 2019 | 1059 | 4% |
| 2020 | 1694 | 11% |
| 2021 | 1352 | 17% |
| 2022 | 2134 | 25% |
| 2023 | 2378 | 35% |
| 2024 | 2608 | 45% |
| 2025 | 2243 | 54% |
Net metering and CO2 in California
EIA-861 (2024): 2,099,871 home net-metered systems in California, 147.7 per 1,000 accounts (rank 2), average 6.1 kW.
6 kW in California: 10,123 kWh a year displaces 1.8 t CO2 at 0.178 kg per kWh, -1.2 t against the average state.
California utilities and solar payback
| California utility | Homes | Price ¢ | Value of 1 kW | Payback at $3.00 |
|---|---|---|---|---|
| Pacific Gas & Electric Co. | 5,047,461 | 31.70 | $535 | 5.6 yr |
| Southern California Edison Co | 4,594,415 | 28.25 | $477 | 6.3 yr |
| Los Angeles Department of Water & Power | 1,410,191 | 23.84 | $402 | 7.5 yr |
| San Diego Gas & Electric Co | 1,364,361 | 32.47 | $548 | 5.5 yr |
| Sacramento Municipal Util Dist | 592,557 | 17.87 | $302 | 10.0 yr |
| Imperial Irrigation District | 142,078 | 17.91 | $302 | 9.9 yr |
| City of Anaheim | 105,839 | 17.11 | $289 | 10.4 yr |
| Modesto Irrigation District | 103,650 | 21.78 | $367 | 8.2 yr |
| City of Riverside | 100,450 | 20.20 | $341 | 8.8 yr |
| Turlock Irrigation District | 80,575 | 16.34 | $276 | 10.9 yr |
| City of Glendale | 77,563 | 33.81 | $570 | 5.3 yr |
| City of Roseville | 63,052 | 18.66 | $315 | 9.5 yr |
California among its neighbours
| Closest to California | Payback, years | kWh per kW | Price, ¢ | Utility-scale solar, points of generation | Miles away |
|---|---|---|---|---|---|
| California (this page) | 5.5 | 1,687 | 32.54 | 26.8 | - |
| Nevada | +7.1 | +130 | -19.39 | +4.0 | 209 |
| Arizona | +5.7 | +63 | -17.22 | -13.5 | 449 |
| Utah | +9.4 | -146 | -19.47 | -9.4 | 529 |
| Idaho | +13.0 | -316 | -20.72 | -18.8 | 638 |
California against its neighbours in the payback ranking
- +0 places, Hawaii -1.2 years against California
- California, rank 2: 5.5 years
- +2 places, Massachusetts +2.2 years against California
- +3 places, Rhode Island +2.4 years against California
Your numbers for California
Limits in California
California: with the old 30% credit (IRS, ended 2025) payback would be 3.8 years instead of 5.5, so the calculator starts at 0%. No California export rates in our data: output counts at 32.54 ¢. All limits.
Sources for California
- PVWatts v8 (NLR), 5 California cities and one state point: 1,687 kWh per kW
- EIA-860 2025 and EIA-923 2025: 24,831 MW of solar in California
- EIA-861 2024: 2,099,871 net-metered systems in California
- EIA retail sales 2025: 32.54 ¢ per kWh in California
- IRS 25D (ended 2025): 3.8 years in California with it; licences and periods for California
More about California
California electricity hub, California EV charging: 19,997 stations, where California ranks for rooftop solar, 5.5 years against 51 states, California calculators.
Questions
Solar payback in California?
5.5 years at $3.00 a watt; 4.6 at $2.50; 6.4 at $3.50; 1,687 kWh per kW at 32.54 ¢.
California electricity from solar, what share?
26.8% of 2025 net generation, rank 2 of 51, +20.0 points against the nation.
Net metering in California?
2,099,871 systems, 147.7 per 1,000 accounts, rank 2.
California sunshine for solar panels?
1,687 kWh per kW a year at the state point, rank 5 of 51; from 1,430 in San Francisco to 1,682 in San Diego.
Where in California is solar best?
Yes: 16% between San Francisco and San Diego in yearly output.
California utility-scale solar capacity?
24,831 MW in 946 plants (EIA-860), 633 W per resident, rank 10; 8,606 MW proposed.
Winter cut in California solar output?
December to February give 17% of the year; May makes 178 kWh per kW and Jan 83.
California pays half price for exports?
Payback 10.9 years at a 50% retail share.
CO2 displaced in California?
1.8 t a year on 6 kW at 0.178 kg per kWh.
Federal solar credit in California: still available?
Ended 2025 (IRS 25D); with it California payback would be 3.8 years, not 5.5.