Small-scale solar generation in the U.S. has quadrupled in a decade, EIA data show

Electricity from small-scale solar systems in the United States has climbed from 18,812 gigawatthours to 92,979 gigawatthours over the last decade, the Energy Information Administration reported on October 16. That is roughly a fivefold gain in raw arithmetic, and EIA describes it as a quadrupling. California alone produced more than a third of the 2025 total, and four states now sit at the top of the ranking.

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The category is easy to overlook because none of the systems in it is large. Each one is under a megawatt, most are on rooftops, and together they behave like a power plant that nobody dispatches.

EIA’s tally of rooftop solar

In a Today in Energy article by Lindsay Aramayo and Marc Harnish, EIA defines small-scale solar as rooftop or other photovoltaic systems smaller than 1 megawatt of capacity. The agency says generation from those systems rose from 18,812 GWh to 92,979 GWh over the last decade, a growth the article headlines as a quadrupling. The biggest single-year jump came in 2022, when total generation grew 25% from the year before during a period of record capacity growth, and EIA says growth has slowed since then.

Utilities do not meter this output, so the numbers are estimates. Much of the underlying count comes from Form EIA-861, the Annual Electric Power Industry Report, which the agency describes as a census of United States electric utilities. It collects the number of customers with small-scale systems and their aggregate capacity, and the latest final data year is 2025. Because utilities generally do not know how much their customers’ panels generate, EIA converts capacity into generation with models from the National Renewable Energy Laboratory, including its PVWatts calculator, which estimates the energy output of grid-connected photovoltaic systems. It uses commonly applied tilt angles and orientations from California as inputs for other states.

The estimates carry adjustments of their own. The EIA-861 page says capacity reported in direct-current units is converted to alternating current with a factor of 0.8256, and that missing photovoltaic capacity receives a state-level adjustment. EIA also gathers separate data on generators under 1 megawatt that are not net metered, a series that begins in 2010, so the rooftop total rests on more than one reporting stream.

California, Arizona, Texas and Florida lead

California generated 34,411 GWh from small-scale solar in 2025, about 37% of the national total, and its output grew 8% from 2024, mostly from added capacity that rose from 18 gigawatts to 20 gigawatts. Arizona came second at 5,795 GWh, a little over 6% of the total, with growth of 6% in 2025 after a 22% increase between 2022 and 2023. Texas followed at 5,408 GWh and Florida at 5,198 GWh. New York ranks fifth despite weaker sunshine than the southern states.

The growth in the two Sun Belt followers is the starkest part of the table. Texas generation rose from 391 GWh in 2016 to 5,408 GWh in 2025, and Florida’s rose from 205 GWh to 5,198 GWh over the same stretch, which is more than thirteenfold for Texas and more than twenty-fivefold for Florida by simple division.

Net metering and state incentives behind the climb

EIA ties much of the pattern to state policy. In California, the Net Energy Metering 2.0 program ran through April 2023 and offered higher compensation for exported power than the Net Billing Tariff that replaced it, and capacity installed under the older program was grandfathered, which encouraged installations before the change. The California Public Utilities Commission says that since April 15, 2023, customers applying for interconnection have taken service on the new net billing tariff, under which exported power is credited at a rate reflecting its value to the grid rather than at the full retail rate.

Other states use different tools. Arizona offers a 25% state income-tax credit for rooftop solar, Texas and Florida rely on property tax exemptions and other state or utility programs, and EIA credits New York’s fifth place to capacity growth from technology improvements and state incentives. New Jersey, Massachusetts and Illinois also have incentive programs for small-scale solar, the article says.

Small-scale systems are one slice of a faster-growing solar fleet. In its October outlook, EIA’s Short-Term Energy Outlook projects that all solar, utility-scale included, will supply 8% of U.S. generation in 2026 and 9% in 2027. The rooftop segment is the part that sits behind customers’ meters, which is why it is estimated from survey data and weather models instead of being read off a plant’s output.

The four leading states also account for a majority of the national figure. Adding EIA’s state numbers for California, Arizona, Texas and Florida gives 50,812 GWh, or about 55% of the 92,979 GWh total, by simple arithmetic on the published figures. The concentration means national trends in rooftop solar depend heavily on a few state policy decisions.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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