PVWatts Photovoltaic Energy Calculator

PVWATTS calculates electrical energy produced by a grid-connected photovoltaic (PV) system. Researchers at the National Renewable Energy Laboratory developed PVWATTS to permit non-experts to quickly obtain performance estimates for grid-connected PV systems within the United States and its territories. PVWatts determines the energy production and cost savings of grid-connected photovoltaic (PV) energy systems throughout the world. The PVWatts calculator was developed by the National Renewable Energy Research Lab's Electric Systems Center Resource Integration Section.