Every number traces to a source you can check.
Chart Solar is grounded in public, commercially licensed datasets. Each source below is listed with its license and the attribution it requires. The methodology behind the models is at /methodology.
DSIRE — export policy & incentives
CC-BY-SA 4.0Net-metering and export-compensation regimes — plus state and utility incentives — are sourced from DSIRE, maintained by the NC Clean Energy Technology Center at NC State University. Under CC-BY-SA 4.0 every DSIRE-derived value we surface carries its attribution.
DSIRE © 2026, NC Clean Energy Technology Center, CC-BY-SA 4.0 (https://www.dsireusa.org)
dsireusa.org ↗NREL NSRDB — solar irradiance
CC-BY 4.0Hourly satellite measurements of the sunlight landing at your address (irradiance) come from NREL's National Solar Radiation Database (PSM3). The hour-by-hour production model runs on top of it. Cached by grid cell, never queried per user.
nsrdb.nrel.gov ↗OpenEI URDB — utility tariffs
CC0 1.0Retail electricity rate structures are resolved from NREL / OpenEI's Utility Rate Database. Released to the public domain under CC0; no attribution required.
openei.org ↗EIA-861 — utility service territories
US public domainThe utility your address maps to — the crosswalk that keys export policy and tariffs to an EIA utility id — comes from the US Energy Information Administration's Form EIA-861 annual electric-utility survey.
eia.gov ↗LBL Tracking the Sun — cost benchmarks
CC-BY 4.0Regional $/W install-cost benchmarks are derived from Lawrence Berkeley National Laboratory's Tracking the Sun dataset (the CC-BY data, not the report PDF).
emp.lbl.gov ↗Google Solar API — roof geometry
attribution requiredWhen we measure your roof for you, the roof render and the auto-filled tilt / azimuth / size originate from the Google Solar API.
Source: Includes solar data from Google
developers.google.com ↗DSIRE is licensed CC-BY-SA 4.0. We attribute it at the row level: wherever a forecast surfaces a DSIRE-sourced export-policy fact, the resolved regime and its attribution string appear alongside the number.