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The U.S. Energy Information Administration estimates that generation from small-scale solar systems rose from 18,812 gigawatt-hours to 92,979 GWh over the last decade. California produced 37% of the national total in 2025, while the agency says growth has continued but slowed since a sharp increase in 2022.
U.S. generation from small-scale solar rose from 18,812 gigawatt-hours in 2016 to an estimated 92,979 GWh in 2025, according to an analysis published October 16 by the U.S. Energy Information Administration. The increase—nearly fivefold—reflects a decade of expanding rooftop and other solar photovoltaic systems smaller than one megawatt, though the pace of growth has eased since 2022.
The EIA identifies California, Arizona, Texas and Florida as the four largest state producers of small-scale solar generation. Their strong solar resources are one factor in their output. New York, which has less abundant solar resources, ranked fifth; the agency links its position to capacity growth supported by technology improvements and state incentives.
California led by a wide margin in 2025, generating 34,411 GWh, or 37% of the U.S. total. Its small-scale solar generation increased 8% from 2024, as installed capacity rose from 18 gigawatts to 20 gigawatts. Arizona was second, producing 5,795 GWh, more than 6% of the U.S. total; its generation grew 6% year over year in 2025.
Texas and Florida have also added substantial rooftop solar output over the decade. EIA estimates Texas generation increased from 391 GWh in 2016 to 5,408 GWh in 2025, while Florida rose from 205 GWh to 5,198 GWh. The agency reports that incentives in these states include property tax exemptions and programs that vary by state and, in some cases, utility.
Rooftop Solar’s Changing State Map
The national increase shows that small-scale solar has become a much larger source of U.S. electricity, but the benefits and growth are uneven across states. California alone supplied over a third of estimated generation in 2025, while fast-growing output in Texas and Florida points to a widening geographic footprint beyond the states that have traditionally dominated rooftop solar.
The figures also show how policy and local market conditions can shape installation patterns. EIA says customer incentives have supported growth in several states, including places with lower solar resources. For households, utilities and policymakers, that matters because rooftop systems add generation across distribution networks rather than only at large power plants. The report does not quantify effects on electricity bills, grid reliability or emissions, so the generation figures should not be read as a direct measure of those outcomes.
California’s experience illustrates how changes to compensation rules can affect the timing of installations. EIA says the state’s earlier net-metering program offered higher compensation for electricity exported to the grid than the subsequent tariff, and that systems installed under the earlier program were grandfathered in. The agency connects that transition to a period of capacity growth, but its analysis does not isolate the policy’s effect from other factors.
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A Decade of Capacity Growth
The EIA’s comparison covers a decade, from 18,812 GWh in 2016 to 92,979 GWh in 2025. The largest year-over-year national increase in the report occurred in 2022, when estimated generation rose 25% from the previous year amid record capacity growth. EIA says the rate of growth has declined since then, even as generation has continued to increase.
California’s net energy metering program, known as NEM 2.0, remained available through April 2023. It offered higher export compensation than the later Net Billing Tariff, or NEM 3.0. According to EIA, capacity built under NEM 2.0 was grandfathered into the earlier terms, encouraging installations before the new tariff took effect. Arizona offers customers a 25% state income-tax credit and other incentives, while New York, New Jersey, Massachusetts and Illinois also have programs supporting small-scale solar.
The report’s figures are estimates, not direct readings of all rooftop output. EIA surveys electric utilities for customer counts and aggregated system capacity, but utilities may not know how much electricity rooftop solar generates on their distribution networks. The agency estimates generation using tools including the National Renewable Energy Laboratory’s System Advisor Model and PVWatts. It uses information on common California panel tilt angles and orientations as inputs intended to represent systems in other states.
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How Rooftop Output Is Estimated
The national and state generation totals are EIA estimates, because utilities do not necessarily measure all electricity produced by rooftop systems connected to their distribution networks. The agency describes the modeling tools and input assumptions it uses, but the report does not provide a direct meter reading for total rooftop generation.
The analysis also does not quantify how much of the decade-long increase was caused by incentives, technology improvements, falling equipment costs, customer demand or other factors. EIA links policies to growth in particular states and discusses California’s compensation changes, but does not assign a specific share of the national increase to any one cause. The report’s supplied data end in 2025; figures for 2026 are not included.
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Future Estimates and Growth Rates
The next point of comparison will be whether EIA’s subsequent estimates show small-scale generation continuing to rise and whether the slower growth rate reported since 2022 persists. The agency’s method depends on utility survey information about customers and capacity alongside solar-production modeling, so updated estimates can refine the picture as new installations are reported.
Readers should distinguish annual generation from installed capacity: generation measures electricity produced over a period, while capacity describes the systems’ rated generating power. The report provides a 2024-to-2025 capacity increase for California but does not give a national capacity total in the supplied figures. It also does not announce a specific date for a follow-up analysis.
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Key Questions
What does the EIA mean by small-scale solar?
The report defines it as solar photovoltaic systems smaller than one megawatt of capacity, including rooftop systems. The generation estimates cover electricity produced by these systems.
How much did U.S. small-scale solar generation increase?
EIA estimates output rose from 18,812 GWh in 2016 to 92,979 GWh in 2025, nearly five times as much. These are agency estimates rather than a direct reading of every rooftop system.
Which state produced the most rooftop solar power in 2025?
California, with estimated generation of 34,411 GWh, equal to 37% of the U.S. total. Arizona ranked second with 5,795 GWh.
Is rooftop solar still growing as quickly as it did in 2022?
No. EIA says generation continues to grow year over year, but its growth rate has declined since 2022. In 2022, national generation rose 25% from the previous year.
Are the generation totals directly measured?
Not in full. Utilities may not know the amount generated by rooftop systems on their distribution networks, so EIA estimates output using utility survey data and modeling tools such as PVWatts and the System Advisor Model.
Source: primary
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