Solar Maps and Calculators

Solar maps published by the National Renewable Energy Laboratory (NREL) provide average daily total solar resource information, averaged by month and by year, on grid cells of approximately 40 km by 40 km in size. The insolation values represent the solar resource available to a flat plate collector, such as a photovoltaic panel, oriented due south and tilted up from the horizontal at an angle equal to the panel’s latitude.

You can see the maps here.

You can also find a calculator on the NREL site that allows non-experts to obtain performance estimates for grid-connected PV systems within the United States.

You can access the calculator here.

You can learn more about the calculator here.