This project supports the Solar America Initiative by: (1) Providing solar radiometric measurements, data, and related technical information support to NREL Measurements and Characterization Task; NREL Reliability and Durability Task; Systems and component testing and evaluation for the SAI TPPs; Requests from industry; (2) Producing credible radiometric measurements traceable to recognized standards for performance and Industry applications in accordance with IS0-17025 accreditation scope; (3) Contributing to consensus codes and standards for performance and measurement techniques for NREL R&D, SAI TPPs, and industry applications; (4) Maintain stability of the NREL solar radiation reference (absolute cavity radiometers); (5) Execute high quality detailed radiometric calibrations for broadband and spectral radiometers to meet NREL research and PV industry needs; (6) Participate in national and international consensus standards development, contributing technical expertise, data, and analysis where appropriate; (7) Provide technical information on solar radiation resource data and applications to meet research and industry needs; and (8) Transfer technology in this area to other researchers and industry via publications and conference papers and presentations.