Environment — entry 013 of 18
PVWatts
PVWatts estimates the energy production and cost of grid-connected photovoltaic systems anywhere in the world, given basic system specs like capacity, tilt, and array type. The National Renewable Energy Laboratory's developer portal was renamed to the National Laboratory of the Rockies (NLR) and its host retired on 2026-05-29 — the API itself is unchanged, just served from developer.nlr.gov instead of the old developer.nrel.gov, which no longer resolves.
AuthenticationAPI KeySign up with the provider to obtain credentials.
HTTPSSupportedTraffic is encrypted in transit.
CORSEnabledCallable directly from browser JavaScript.
PricingFreeNo paid tier — free for the documented use case.
FormatsJSON, XMLResponses can be requested as JSON or XML.
GreatAPIs Score
Score70
Authentication15/25API key required
Pricing20/20Free to use
Docs0/20No docs or spec available
Formats15/15Supports 2 response formats
Freshness20/20Verified within 6 months
Embed this badge
<a href="https://greatapis.com/api/pvwatts/"><img src="https://greatapis.com/badge/pvwatts.svg" alt="Scored 70 on greatapis.com"></a>Auth quickstart
- Sign up with the provider to get an API key.
- Send it on every request as a header
Authorization: <key> - The exact header isn't documented — Authorization is a common default; confirm in the provider's docs.
Stored keyNo key stored
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.