#Solar Resource Models and Tools
The National Renewable Energy Laboratory (NREL)'s Renewable Resource Data Center (RReDC) features the following solar resource models and tools that are available for use by the public.
This algorithm estimates clear sky direct beam, hemispherical diffuse, and total hemispherical solar radiation for horizontal planes.
This model computes clear sky spectral direct beam, hemispherical diffuse, and hemispherical total irradiances on tilted or horizontal planes.
DISC estimates direct beam irradiance from user-supplied hourly average measured global horizontal data.
Visualize, explore, and download solar resource data from the National Solar Radiation Database.
PVWatts® Calculator is a web application that estimates the electricity production of a grid-connected roof- or ground-mounted photovoltaic system based on a few simple inputs.
The System Advisor Model (SAM) is a performance and financial model designed to facilitate decision making for people involved in the renewable energy industry.
##Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS)
SMARTS computes clear sky spectral irradiances for a set of user-specified atmospheric conditions.
##Solar and Moon Position Algorithm (SAMPA)
SAMPA calculates the Sun and Moon position with very low uncertainty based on location, date, and time inputs for the years -2000–6000. This algorithm can be used for solar eclipse monitoring and estimating the influence on solar irradiance.
##Solar Position Algorithm (SPA)
SPA calculates the solar position with very low uncertainty based on location, date, and time inputs for the years -2000–6000.
##Solar Position and Intensity (SOLPOS)
SOLPOS calculates the solar position and intensity based on location, date, and time inputs for the years 1950–2050.
- October 7, 2016: These pages are in the process of being relocated from RReDC. All codes and executables are still hosted on RReDC.