About Device Performance and Calibration

The NREL Photovoltaic (PV) Device Performance group provides certification, testing, and calibration services that help set global standards while defining industry best practices. We help PV researchers, manufacturers, and labs assess the performance of their products.

We're the only U.S. laboratory certified to calibrate primary reference cells, secondary reference cells, secondary reference modules, cells, and modules. We perform calibrations and measure performance parameters—such as efficiency—on the entire range of PV technologies, achieving measurement uncertainties equal to or lower than any other lab in the world. We test hundreds of cells and modules every month and consult with hundreds of entities on PV measurements and solar simulation each year.

Capabilities

Our lab has been accurately measuring the performance of PV devices for decades and has more than 190 years of combined professional experience. We know the importance of precision, accuracy, and timeliness in the growth and validation of the PV industry and understand that, in a competitive global market, turnaround times can make or break opportunities. For this reason, we offer rigorous, reliable, and comprehensive measurements with six-week or faster turnaround times.

We design, develop, and implement the hardware, software, and procedures to measure current-versus-voltage (I-V) characteristics as a function of temperature, spectrum, and intensity for single- and multi-junction cells and modules. We test devices of all types of PV technologies from around the world to ensure consistency and accuracy of PV performance measurements.

Our capabilities include:

Measuring I-V and quantum efficiency of any type of PV cell or module
Measuring the temperature dependence of reference cell quantum efficiency
Measuring linearity of reference cell current versus irradiance
Calibrating primary and secondary reference cells
Calibrating secondary reference modules (golden modules)
Measuring the temperature dependence of module performance
Measuring the temperature dependence of module quantum efficiency
Testing flat-plate and concentrator modules on sun-tracking systems.

These combined systems capabilities allow us to accurately measure the characteristics of any conceivable PV cell or module technology. Our overlapping capabilities allow us to cross-check, understand, and account for the various error sources of each test bed.

Accreditation

ISO 17025

We are accredited by the American Association for Laboratory Accreditation to International Organization for Standardization (ISO) 17025 standards for primary reference cell, secondary reference cell, and secondary module calibrations following American Society for Testing and Materials (ASTM) and International Electrotechnical Commission (IEC) standards for PV.

This accreditation gives our results the same stature as those performed by a national metrology laboratory, such as the National Institute of Standards and Technology, but with the added breadth and depth of NREL's capabilities. See the 17025 certificate of accreditation.

ISO 9001

All numerical values reported by our group outside the scope of the ISO 17025 accreditation are accredited to ISO 9001 standards by Orion Registrar. The ISO 9001 quality system follows the group's ISO 17025 quality systems with the notable exception of a formal uncertainty analysis. There are other minor deviations, such as the lack of a check list for ISO 9001 calibrations. See the 9001 certificate of accreditation.

Our facility for calibrating primary reference cells is one of four in the world certified in accordance with the World Photovoltaic Scale.

Standards

As a global industry, it's important that PV products be tested and qualified the same way everywhere in the world. Harmonized standards help make PV cost-effective and enable access to markets everywhere.

We cooperate internationally through intercomparisons and technical interactions to provide the PV community with a path of traceability to standards. We also help develop consensus in U.S. and international PV standards by participating in ASTM and IEC standards groups.