In order to determine how much sunlight is available for electricity generation, you must know the sun resource for the area where you live. This map indicates the average number of hours per day that photovoltaic (solar) cells can generate electricity.

Locate Starr County on the map. Use the color to determine the number of sun hours (kWh/square meter/day); write that number on Line 1 of the chart for solar energy calculations.

The solar energy resource map is from http://www.nrel.gov/gis/solar.html