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PVWatts Calculator National Renewable Energy Laboratory

NREL's PVWatts® Calculator

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations.

NREL will be updating a few PVWatts® default values,
for example the default DC to AC Ratio changes to 1.2 from 1.1.
Note that you will still be able to change the inputs to match the defaults from this version.

We will be changing the default weather data selection to the NREL National Solar Radiation Database from the latest Physical Solar Model (PSM) TMY.
This change will also add many countries currently without data in PVWatts.
This dataset replaces current access to SolarAnywhere data.