Please note that the Solar Radiation Monitoring Laboratory takes full responsibility for any inaccuracies that may occur. The United States National Climatic Data Center . A Normal Incident Pyrheliometer , used to determine the amount of solar irradiance emitted from the direction of the sun. The United States National Oceanic and Atmospheric Administration . There is no formal definition for this term.
Typical usage defines it as any energy source that is used faster than it is replenished .
The National Renewable Energy Laboratory , a U. S. National Laboratory specializing in developing technologies and procedures for using renewable energy sources.