NREL's PVWatts® API estimates the energy production of grid-connected photovoltaic (PV) energy systems based on a few simple inputs.
NEWS: Version 8 of the PVWatts Calculator web API is available as of 2022-11-14. This exciting update adds a bifacial module option, a new input for monthly irradiance losses, new inputs for specifying albedo, and updates the photovoltaic module, inverter, and thermal effects models to use more detailed and industry-accepted algorithms. PVWatts V8 also updates the weather data to 2020 TMY data from the NREL National Solar Radiation Database (NSRDB) for locations covered by the database. (The NSRDB weather data used in PVWatts V6 is from around 2015.) This update provides production estimates based on the latest, state-of-the art models from NREL that may differ from the V6 estimates, depending on the location and inputs. From a coding perspective, PVWatts V8 replaces the pvwattsv5 compute module with pvwattsv8 so that the PVWatts Calculator, web API, and implementation of PVWatts in the System Advisor Model (SAM) all use the same underlying model. The PVWatts V6 API will be deprecated six months after the release of PVWatts V8. Deprecated versions of PVWatts are not available as web APIs, but are available via the SAM Simulation Core (SSC) API, which requires a local installation of the API with separate code to access weather data via the NSRDB API. Contact email@example.com if you have any questions.
Version 8 is the current version of the PVWatts API, and is the version used by NREL's PVWatts Calculator. Updates from Version 6 include using the latest NREL National Solar Radiation Database (NSRDB). V8 also adds a bifacial module option, a new input for monthly irradiance losses, and updates the photovoltaic module, inverter, and thermal effects models to use more detailed and industry-accepted algorithms.
Version 6 has been replaced by Version 8. Version 6 will be decommissioned in early 2024.