Small-scale solar photovoltaic generation in the United States has increased nearly fivefold over the past decade, rising from 18,812 gigawatt-hours (GWh) in 2016 to 92,979 GWh in 2025, according to the U.S. Energy Information Administration (EIA).

In an analysis published, the EIA attributes the growth to the expansion of rooftop solar capacity, with the four largest state producers — California, Arizona, Texas and Florida — benefiting from abundant solar resources. New York ranks fifth despite lower solar resources, supported by capacity growth, technology improvements and state incentives.

California accounts for 37% of U.S. small-scale solar generation

California was the largest producer of small-scale solar electricity in 2025, accounting for 37% of the U.S. total, or 34,411 GWh. Generation in the state increased by 8% year on year, largely due to capacity growth, with installed small-scale solar capacity rising from 18 gigawatts (GW) in 2024 to 20 GW in 2025.

Arizona ranked second, generating 5,795 GWh, equivalent to more than 6% of the national total. Its small-scale solar generation grew by 6% in 2025. The largest annual increase in the state occurred between 2022 and 2023, when generation rose by 22%. The EIA notes that Arizona offers customers a 25% state income-tax credit and other incentives for installing rooftop solar systems.

Texas and Florida have also recorded substantial growth over the past decade as additional capacity has been installed. Small-scale solar generation in Texas rose from 391 GWh in 2016 to 5,408 GWh in 2025. In Florida, it increased from 205 GWh to 5,198 GWh over the same period. Both states offer property tax exemptions and other incentive programmes, some of which are specific to individual states or utilities.

State incentives support rooftop solar growth

The EIA also highlights the role of incentive programmes in states with lower solar irradiance. New York, the fifth-largest producer of small-scale solar electricity, has supported deployment through incentives, while New Jersey, Massachusetts and Illinois also operate programmes aimed at encouraging rooftop solar adoption.

In California, changes to net energy metering policies partly explain the particularly strong growth recorded in 2022. U.S. small-scale solar generation increased by 25% that year amid record capacity growth. California's Net Energy Metering (NEM) 2.0 programme, which offered higher compensation for electricity exported to the grid than the subsequent Net Billing Tariff, or NEM 3.0, remained available through April 2023. Capacity installed under NEM 2.0 was grandfathered in, encouraging installations before the new tariff took effect.

Despite the continued annual increase in small-scale solar generation, the EIA reports that the growth rate has declined since 2022.

EIA estimates rooftop solar generation using modelling tools

The EIA defines small-scale solar as photovoltaic systems with a capacity of less than 1 megawatt (MW). Its estimates draw on surveys of electric utilities to collect data on the number of customers with small-scale solar systems and their aggregated capacity.

Because utilities do not necessarily know how much electricity rooftop solar systems generate across their distribution networks, the agency estimates generation using tools including the National Renewable Energy Laboratory's System Advisor Model and PVWatts. The EIA also uses data on commonly applied tilt angles and orientations for small-scale solar systems in California as inputs to represent these characteristics in other states.

The analysis is based on the EIA's Annual Electric Power Industry Report and was published in its Today in Energy series on 16 October 2026.