Is Solar Worth It Where You Live?

PlainSolarData aggregates state-level residential and small-commercial solar capacity, deployment trends, and incentive program data for all 50 states plus DC. The dataset is built from the Energy Information Administration (EIA) electric power monthly reports, the National Renewable Energy Laboratory (NREL) Open PV project, the SEIA/Wood Mackenzie quarterly market reports where licensable, and the DSIRE database of state and utility incentive programs. Each state page surfaces installed capacity, year-over-year growth, average installed cost per watt, net-metering policy status, and incentive program counts.

Net metering is a billing arrangement under which a customer who generates their own electricity (typically with rooftop solar) receives a credit on their utility bill for surplus electricity they export back to the grid. Under traditional full-retail net metering, every exported kilowatt-hour offsets one consumed kilowatt-hour at the same retail rate. Many states have transitioned to "net billing" structures that compensate exports at a lower rate (avoided cost or wholesale rate), changing the economics of residential solar materially. State policy varies widely, and we track the current rule on each state page.

Solar capacity is measured in megawatts (MW) — the maximum instantaneous power output the system can produce under standard test conditions. Solar generation is measured in megawatt-hours (MWh) — actual energy produced over time. A 5 megawatt solar array does not produce 5 megawatt-hours every hour; it produces 5 MWh only at peak sun. Annual generation depends on the location's capacity factor, which for U.S. utility-scale solar typically runs 18 to 28 percent. We use MW for installed capacity and MWh for actual generation, following EIA conventions.

The federal Investment Tax Credit allows residential and commercial solar system owners to claim a credit against federal income tax equal to a percentage of the system cost. The Inflation Reduction Act of 2022 set the residential credit at 30 percent through 2032, stepping down to 26 percent in 2033 and 22 percent in 2034 before expiring for residential systems. Commercial systems remain eligible under a longer schedule with bonus adders for domestic content and energy-community siting. The ITC is a credit (offsetting tax liability) rather than a deduction (offsetting taxable income).

EIA publishes monthly Electric Power Monthly reports approximately 90 days after the reporting month. SEIA quarterly market reports lag by roughly 60 days. DSIRE incentive-program data is updated continuously by the North Carolina Clean Energy Technology Center as state and utility programs change. PlainSolarData refreshes from each upstream source on its own ETL cadence and surfaces source dates on every state page. New utility-scale projects appear within one refresh of EIA reporting; new residential incentive programs may take longer to flow through DSIRE.

A Solar Renewable Energy Certificate (SREC) represents the environmental attributes of one megawatt-hour of solar electricity generation, separable from the underlying electricity itself. In states with a Renewable Portfolio Standard that includes a solar carve-out, regulated utilities must purchase SRECs to meet compliance. System owners can sell their SRECs to utilities or aggregators on the open market. SREC values vary widely by state — they have historically been a major revenue stream in NJ, MA, MD, PA, OH, IL, and DC, but program details and prices change frequently as compliance markets mature.