Solar in Maine: payback, sun by city and utility-scale capacity
Maine pays back in 8.5 years at $3.00 a watt (rank 6 of 51), 5.0 years shorter than the middle state. 1,267 kWh per kW (rank 43) at 27.78 ¢ (rank 6 from the top): price of power drives it. Across 5 Maine cities, yearly output runs from 1,241 kWh per kW in Bangor to 1,312 in Portland. Jul is the best month at 136 kWh per kW and Dec the worst at 58. Utility-scale solar in Maine: 960 MW in 175 plants, 10.0% of 2025 generation; 578 MW more under construction or planned.
Maine: payback 8.5 years, rank 6 of 51
| Measure | Value | Rank of 51 | Median state |
|---|---|---|---|
| Output of 1 kW a year, kWh | 1,267 | 43 | 1,372 |
| Home price, ¢ per kWh | 27.78 | 6 | 15.37 |
| Value of 1 kW a year | $352 | 6 | $222 |
| Payback at $3.00 a watt | 8.5 years | 6 | 13.5 years |
EIA-861 (2024): 15,328 home net-metered systems in Maine, 20.6 per 1,000 accounts (rank 20), average 8.0 kW.
Sizes and prices per watt in Maine
| Maine kW | kWh a year | Value a year | Cost at $2.50 | At $3.00 | At $3.50 | t CO2 |
|---|---|---|---|---|---|---|
| 4 | 5,068 | $1,408 | $10,000 | $12,000 | $14,000 | 0.7 |
| 6 | 7,601 | $2,112 | $15,000 | $18,000 | $21,000 | 1.1 |
| 8 | 10,135 | $2,816 | $20,000 | $24,000 | $28,000 | 1.4 |
| 10 | 12,669 | $3,519 | $25,000 | $30,000 | $35,000 | 1.8 |
| 12 | 15,203 | $4,223 | $30,000 | $36,000 | $42,000 | 2.1 |
| Maine $ per watt | 100% retail | 75% | 50% | 25% |
|---|---|---|---|---|
| $2.00 | 5.7 | 7.6 | 11.4 | 22.7 |
| $2.50 | 7.1 | 9.5 | 14.2 | 28.4 |
| $3.00 | 8.5 | 11.4 | 17.0 | 34.1 |
| $3.50 | 9.9 | 13.3 | 19.9 | 39.8 |
| $4.00 | 11.4 | 15.2 | 22.7 | 45.5 |
Maine: 1,267 kWh/kW × 27.78 ¢ = 352 a year per kW; the 30% column (6.0 years at $3.00) is arithmetic only.
CSVSun inside Maine: 5 cities, 6% apart
| Maine city | kWh per kW a year | Against state point | Sun, kWh/m2 a day | Payback at $3.00 | Residents |
|---|---|---|---|---|---|
| Portland | 1,312 | +3.6% | 4.52 | 8.2 | 68,505 |
| Lewiston | 1,307 | +3.2% | 4.69 | 8.3 | 37,886 |
| Bangor | 1,241 | -2.1% | 4.50 | 8.7 | 31,663 |
| Sanford | 1,273 | +0.5% | 4.55 | 8.5 | 22,095 |
| Waterville | 1,257 | -0.8% | 4.55 | 8.6 | 16,704 |
Maine state point 44.22, -69.78; city points Portland 43.63, -70.19; Lewiston 44.09, -70.17; Bangor 44.83, -68.79; Sanford 43.42, -70.76; Waterville 44.55, -69.66. Panel and method: solar method.
Output by month in Maine cities: 12 rows
| Maine month | Portland | Lewiston | Bangor | Sanford | Waterville |
|---|---|---|---|---|---|
| Jan | 74.1 | 82.7 | 72.4 | 75.4 | 78.5 |
| Feb | 92.9 | 94.3 | 92.2 | 96.5 | 97.3 |
| Mar | 117.9 | 126.8 | 122.6 | 113.1 | 127.4 |
| Apr | 139.9 | 131.8 | 124.5 | 118.8 | 127.4 |
| May | 139.6 | 132.9 | 133.3 | 135.6 | 127.6 |
| Jun | 134.6 | 129.8 | 126.9 | 130.4 | 129.7 |
| Jul | 138.8 | 143.8 | 136.6 | 136.4 | 134.3 |
| Aug | 140.7 | 128.4 | 126.4 | 134.9 | 124.5 |
| Sep | 116.5 | 117.8 | 111.4 | 112.3 | 112.2 |
| Oct | 90.5 | 86.9 | 80.4 | 93.8 | 81.3 |
| Nov | 67.0 | 67.1 | 58.9 | 65.6 | 62.8 |
| Dec | 59.7 | 64.6 | 55.0 | 60.5 | 54.2 |
Maine: 5 cities, best month 144 and worst 54 kWh per kW across them.
CSVBest and worst month in Maine: Jul 136, Dec 58 kWh per kW
| Maine month | kWh per kW | Price ¢ | Value per kW | kWh per kW per sun unit |
|---|---|---|---|---|
| Jan | 80.2 | 26.13 | $20.96 | 0.85 |
| Feb | 88.0 | 26.25 | $23.10 | 0.83 |
| Mar | 124.8 | 28.27 | $35.28 | 0.81 |
| Apr | 127.1 | 28.11 | $35.73 | 0.77 |
| May | 129.9 | 27.91 | $36.26 | 0.75 |
| Jun | 128.2 | 28.14 | $36.08 | 0.73 |
| Jul | 135.7 | 27.98 | $37.97 | 0.72 |
| Aug | 128.5 | 28.25 | $36.30 | 0.72 |
| Sep | 114.3 | 27.98 | $31.98 | 0.74 |
| Oct | 87.5 | 26.63 | $23.30 | 0.78 |
| Nov | 64.3 | 27.85 | $17.91 | 0.81 |
| Dec | 58.3 | 30.39 | $17.72 | 0.83 |
Maine: December to February give 18% of a year (rank 23 of 51, 1 = most winter); the best month is 2.3 times the worst. Output per unit of sun is highest in Jan (0.85) 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 Maine is not modelled separately.
Utility-scale solar in Maine: 960 MW
Maine: 960 MW of operable utility-scale solar in 175 plants across 16 counties (EIA-860, 2025), rank 30 of 51; 697 W per resident, rank 7. Solar made 10.0% of Maine's net generation in 2025 (EIA-923), rank 10, +3.2 points against the national share. Biggest plants: Three Corners Solar in Waldo County, 110 MW (2024); Farmington Solar in Franklin County, 77 MW (2021); Sanford Solar in York County, 49 MW (2020). By county: Waldo 131 MW, York 111 MW, Franklin 103 MW, Kennebec 102 MW. Proposed: 102 MW under construction (2 plants) and 476 MW planned (11 plants); batteries 239 MW running and 15 MW proposed.
| Maine year | MW added | Cumulative share of today's MW |
|---|---|---|
| 2019 | 0 | 0% |
| 2020 | 49 | 5% |
| 2021 | 144 | 20% |
| 2022 | 187 | 40% |
| 2023 | 168 | 57% |
| 2024 | 361 | 95% |
| 2025 | 35 | 98% |
Net metering and CO2 in Maine
EIA-861 (2024): 15,328 home net-metered systems in Maine, 20.6 per 1,000 accounts (rank 20), average 8.0 kW.
6 kW in Maine: 7,601 kWh a year displaces 1.1 t CO2 at 0.141 kg per kWh, -1.9 t against the average state.
Maine utilities and solar payback
| Maine utility | Homes | Price ¢ | Value of 1 kW | Payback at $3.00 |
|---|---|---|---|---|
| Central Maine Power Co | 577,955 | 22.37 | $283 | 10.6 yr |
| Versant Power | 137,906 | 27.50 | $348 | 8.6 yr |
| Eastern Maine Electric Coop | 10,803 | 17.06 | $216 | 13.9 yr |
| Houlton Water Company | 3,907 | 11.95 | $151 | 19.8 yr |
Maine among its neighbours
| Closest to Maine | Payback, years | kWh per kW | Price, ¢ | Utility-scale solar, points of generation | Miles away |
|---|---|---|---|---|---|
| Maine (this page) | 8.5 | 1,267 | 27.78 | 10.0 | - |
| New Hampshire | +1.2 | -9 | -3.22 | -10.0 | 111 |
| Massachusetts | -0.8 | +10 | +2.70 | -0.8 | 154 |
| Vermont | +2.2 | -42 | -4.86 | +0.3 | 154 |
| Rhode Island | -0.7 | +28 | +1.68 | -2.9 | 188 |
Maine against its neighbours in the payback ranking
- -1 places, Rhode Island -0.7 years against Maine
- +0 places, Connecticut -0.6 years against Maine
- Maine, rank 6: 8.5 years
- +2 places, New York +0.4 years against Maine
- +3 places, New Hampshire +1.2 years against Maine
Your numbers for Maine
Limits in Maine
Maine: with the old 30% credit (IRS, ended 2025) payback would be 6.0 years instead of 8.5, so the calculator starts at 0%. No Maine export rates in our data: output counts at 27.78 ¢. All limits.
Sources for Maine
- PVWatts v8 (NLR), 5 Maine cities and one state point: 1,267 kWh per kW
- EIA-860 2025 and EIA-923 2025: 960 MW of solar in Maine
- EIA-861 2024: 15,328 net-metered systems in Maine
- EIA retail sales 2025: 27.78 ¢ per kWh in Maine
- IRS 25D (ended 2025): 6.0 years in Maine with it; licences and periods for Maine
More about Maine
Maine electricity hub, Maine EV charging: 650 stations, where Maine ranks for rooftop solar, 8.5 years against 51 states, Maine calculators.
Questions
Solar payback in Maine?
8.5 years at $3.00 a watt; 7.1 at $2.50; 9.9 at $3.50; 1,267 kWh per kW at 27.78 ¢.
Maine utility-scale solar capacity?
960 MW in 175 plants (EIA-860), 697 W per resident, rank 7; 578 MW proposed.
Maine sunshine for solar panels?
1,267 kWh per kW a year at the state point, rank 43 of 51; from 1,241 in Bangor to 1,312 in Portland.
Maine electricity from solar, what share?
10.0% of 2025 net generation, rank 10 of 51, +3.2 points against the nation.
Where in Maine is solar best?
Yes: 6% between Bangor and Portland in yearly output.
Net metering in Maine?
15,328 systems, 20.6 per 1,000 accounts, rank 20.
Winter cut in Maine solar output?
December to February give 18% of the year; Jul makes 136 kWh per kW and Dec 58.
Maine pays half price for exports?
Payback 17.0 years at a 50% retail share.
CO2 displaced in Maine?
1.1 t a year on 6 kW at 0.141 kg per kWh.
Federal solar credit in Maine: still available?
Ended 2025 (IRS 25D); with it Maine payback would be 6.0 years, not 8.5.