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Maine solar electricity was about 18% of state power in 2025
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EIA data show Maine solar electricity supplied 17.9% of the state’s generation in 2025, roughly 2.9 million megawatt-hours (MWh) of about 16.2 million MWh total. That 2.9 million MWh combines 1.6 million MWh from utility-scale solar (facilities of at least 1 MW) and 1.3 million MWh from small-scale installations such as rooftop systems. The figure appears in the U.S. Energy Information Administration’s Electric Power Monthly and in a Maine Trust for Local News compilation of EIA data. Maine law separately sets renewable targets measured as shares of retail electricity sales: 80% by 2030 and 90% by 2040.
Key takeaways
- Solar share: The U.S. Energy Information Administration reports solar supplied 17.9% of Maine’s electricity generation in 2025, about 2.9 million MWh.
- Utility vs small-scale: Utility-scale solar produced 1.6 million MWh in 2025 and small-scale systems produced 1.3 million MWh, per EIA.
- Total generation and fuel mix: Maine’s statewide total generation was about 16.2 million MWh in 2025; natural gas 34.4%, solar 17.9%, wind 17.7%, hydropower 16.3%, biomass 10.8%.
- Policy target: Maine law calls for 80% of retail electricity sales from renewable sources by 2030 and 90% by 2040, with the remainder from qualifying clean resources.
Table of contents
How EIA counts solar in Maine’s 2025 mix
The U.S. Energy Information Administration separates utility-scale and small-scale solar in its Electric Power Monthly. Utility-scale is defined by the EIA as facilities of at least 1 megawatt; the EIA estimates 1.6 million MWh from those plants in Maine for 2025. Distributed or small-scale systems — rooftop and other behind-the-meter installations that still deliver to the grid — add an estimated 1.3 million MWh. Combining the two gives the 2.9 million MWh solar total that equals 17.9% of the roughly 16.2 million MWh Maine generated in 2025.
That split matters because policy and grid planning use different metrics: generation by fuel (what the EIA reports) versus retail sales (what some statutes target). The EIA’s published tables and the Maine Trust for Local News compilation are the named sources for these numbers.
Where solar sits in Maine’s fuel mix
Solar reached 17.9% in 2025, placing it slightly ahead of wind at 17.7% and behind natural gas at 34.4%, according to EIA figures. Hydropower accounted for 16.3% and biomass 10.8% of the statewide total of about 16.2 million MWh. The EIA also reports that utility-scale sources produced more than 14.8 million MWh in 2025; adding small-scale solar yields the statewide generation figure reported above.
Those shares describe generation, not retail sales or procurement contracts. For example, a utility could meet a retail-sales renewable target through power purchases and credits that do not map one-for-one to on-site generation statistics.
Policy targets and the practical gap between generation and sales
Maine law specifies renewable shares of retail electricity sales: 80% by 2030 and 90% by 2040, with the remainder allowed from qualifying clean resources. The EIA’s generation percentages do not automatically indicate whether utilities have met those retail-sales thresholds, because retail-sales accounting can include purchases, renewable energy certificates, and exclusions.
Meeting the statutory targets will therefore depend on procurement choices, crediting rules and the balance between utility-scale projects and distributed solar. The EIA generation snapshot is a clear indicator of how much electricity came from each fuel in 2025, but it is only one input in judging compliance with the retail-sales goals named in state law.
| Fuel | Share (%) | MWh (where given) |
|---|---|---|
| Natural gas | 34.4% | |
| Solar | 17.9% | 2.9 million MWh |
| Wind | 17.7% | |
| Hydropower | 16.3% | |
| Biomass | 10.8% |
How the next decade could shift the mix
The case for
- Higher small-scale deployment can keep solar’s share near or above its 2025 level because distributed systems already supplied about 1.3 million MWh in 2025.
- If utilities increase contracted renewable purchases and build more utility-scale solar, the generation share measured by EIA is likely to rise, supporting progress toward Maine’s 2030 and 2040 statutory targets.
The case against
- Because state targets are defined as shares of retail electricity sales, rising retail demand or accounting differences could slow apparent progress even if generation from renewables grows.
- Grid integration and siting constraints for large projects could limit how fast utility-scale solar expands, leaving growth concentrated in small-scale systems that present different planning challenges.
What to be careful about
- The EIA figures report generation by fuel while Maine’s statutory targets apply to retail electricity sales; the two denominators are not the same and can give different progress signals.
- Nearly half of Maine’s solar generation in 2025 came from small-scale systems, which complicates capacity planning and may not translate directly into utility procurement metrics used for compliance.
- EIA estimates for small-scale generation rely on their data methods; reconciliation between EIA tables and state accounting is necessary to verify year-to-year changes.
The bottom line
EIA data make clear that solar supplied nearly 18% of Maine’s generation in 2025, split roughly evenly between utility-scale and small-scale systems. That generation snapshot is a useful benchmark, but it is not the same metric the state uses in law: Maine’s statutory targets are expressed as shares of retail electricity sales for 2030 and 2040. Comparing progress therefore requires aligning generation data, procurement contracts and the state’s accounting rules. Verifying EIA’s small-scale methodology and reconciling MWh totals with retail-sales accounting will give a clearer picture of how generation shares translate into statutory compliance.
What to watch
- Watch for Maine’s 2030 renewable-sales milestone: the law requires 80% of retail electricity sales to come from renewables by 2030.
- Watch for Maine’s 2040 target implementation: the statute calls for 90% renewable electricity by 2040, with the remaining 10% from qualifying clean resources.
Frequently asked questions
How much electricity did solar produce in Maine in 2025?
The U.S. Energy Information Administration reports solar generated about 2.9 million MWh in Maine in 2025, equal to 17.9% of the state’s approximately 16.2 million MWh total.
What is the difference between utility-scale and small-scale solar in these figures?
EIA defines utility-scale solar as facilities of at least 1 megawatt; utility-scale produced 1.6 million MWh in 2025 while small-scale (rooftop and other distributed systems) produced 1.3 million MWh, per EIA.
Do Maine’s renewable targets use the same measure as the EIA generation share?
No. Maine’s law sets targets as shares of retail electricity sales — 80% by 2030 and 90% by 2040 — whereas the EIA numbers describe electricity generation by fuel, not retail sales accounting.
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