Version 1 of the PVWattsTM calculator allows users to select a photovoltaic (PV) system location from a defined list of options. For locations within the United States and its territories, users select a location from a map of 239 options. For international locations, users select a location from a drop-down menu of options.
The PVWatts Version 1 calculator uses hourly typical meteorological year (TMY) weather data and a PV performance model to estimate annual energy production and cost savings for a crystalline silicon PV system. For locations in the United States and its territories, the PVWatts Version 1 calculator uses NREL TMY data. For other locations, it uses TMY data from the Solar and Wind Energy Resource Assessment Programme, the International Weather for Energy Calculations (Version 1.1), and the Canadian Weather for Energy Calculations. Version 1 offers data only for defined locations. If your U.S. location is not included, you may choose a nearby, similar site or use Version 2.
To use the PVWatts Version 1 calculator, see: