Solar Radiation Research LaboratoryNational Renewable Energy LaboratoryThomas Stoffel, Afshin Andreas, Ibrahim Reda, Mike Dooraghi, Aron Habte, Mark Kutchenreite

Advanced Solar Measurements

Improved Resource and System Performance Models

At the SRRL, researchers use pyranometers, pyrheliometers, pyrgeometers, photometers, and spectroradiometers to provide the solar resource data necessary for renewable energy research and development. Since 1981, researchers have continuously gathered solar radiation information, and they now gather high-resolution data (in 1-minute intervals) from World Meteorological Organization first-class instruments. Staff also perform daily instrument maintenance and annual calibrations to ensure data quality. Measurement activities support a number of Department of Energy renewable energy programs as well as its Atmospheric Radiation Measurement Program, which applies radiometry to climate change research. 

Radiometer Calibrations

Traceable to the World Radiometric Reference

So

High-

Reference absolute cavity radiometers

Annual NREL pyrheliometer comparison

ISO-17025 accredited 

broadband outdoor radiometer calibrations

Standards Development

Domestic and International

• ASTM International • National Institute of Standards and Technology• International Standards Organization• International Electrotechnical Commission• International Energy Agency

The Solar Radiation Research Laboratory (SRRL) has been collecting continuous measuradiation components since 1981. It offers integrated metrology, optics, electronics, and dand provides facilities for outdoor performance testing of new research instrumentation adevices such as photovoltaic modules.The SRRL is located on the National Renewable Energy Laboratory’s South Table Mountwhere it has excellent solar access because of its unrestricted view of the horizon from sthe year. Located at 6,000 ft (1,829 m) above sea level, the SRRL provides a unique outdsupport renewable energy conversion technologies and climate change studies for the U

Automatic solar 

trackers for DNI 

and diffuse

Pyranometers 

and photometers 

for GHI and UV

Spectroradiometer Total sky imager Rotating 

shadowband 

radiometer

NREL calibrates hundreds of instruments annually to ensure data quality. Calibration involves comparing an instrument output signal with a measurement standard traceable toa recognized standard to identifyand eliminate deviations in accuracy. Calibration allows researchers to compare data from different sources,be confident in those data, and produce better estimates of the uncertainty of an instrument, system, or process.

Laboratories

Improving Measurement Science and Technology

The SRRL, a 2,600-square-foot facility completed in 2000, houses:• The Metrology Laboratory, which provides World Radiometric Reference traceability for solar 

absolute cavity radiometers, pyrheliometers, pyranometers, and pyrgeometers. The Metrology Laboratory also provides National Institute of Standards and Technology traceability. 

• The Optical Metrology Laboratory, which ensures that optical radiation resource 

measurement equipment is calibrated to national or international standards to providethe quality and traceability of data.

• The Data Acquisition Laboratory, which collects solar and meteorological data for public 

access from the Measurements and Instrumentation Data Center (www.nrel.gov/midc).

• The Electronics Laboratory, which develops instrumentation systems for collecting solar 

resource measurements.

Presented at the SunShot Grand Challenge Sum

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewab