The DSIRE website provides a fast and convenient method for accessing information about renewable energy and energy efficiency incentives and regulatory policies administered by federal and state agencies, utilities, and local organizations.

Established in 1995, the Database of State Incentives for Renewables & Efficiency is an ongoing project of the North Carolina Solar Center and the Interstate Renewable Energy Council (IREC) funded by the U.S. Department of Energy.
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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.

In a grid-connected PV system, PV modules, wired together to form a PV array, pass DC electricity through an inverter to convert it into AC power. If the PV system AC power is greater than the owner's needs, the inverter sends the surplus to the utility grid for use by others. The utility provides AC power to the owner at night and during times when the owner's requirements exceed the capability of the PV system. - (Read more)

These maps show the general trends in the amount of solar radiation received in the United States and its territories. They are spatial interpolations of solar radiation values derived from the 1961-1990 National Solar Radiation Data Base (NSRDB) and published in the Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors. The data from which these maps were generated can be found one directory down at http://rredc.nrel.gov/solar/old_data/nsrdb/redbook. - (Read more)

The SunSavings^TM Calculator is designed to provide you with a realistic estimate of how much money you can save by adding solar power to your home energy mix. Simply adjust the variables below and click "Calculate My Savings" for a free report customized to your criteria. - (Read more)

Directory of Solar Panel Installers, manufacturers, training and more. - (Read more)