We Make Sunlight!

NREL uses our Solar Simulators

We specialize in solar simulation and PV output measurement for RnD and manufacturing


Why choose us?

We fuel the development and growth of solar energy by helping our customers achieve the highest degree of measurement accuracy, maximizing the return on their solar investments.

We believe

Achieving high measurement accuracy is about the interaction between the PV module, test procedure, and data interpretation. Winners in the industry are the players able to predict PV module performance with higher certainty and lower safety margins.

Why clients work with us

  • Global presence; local service teams
  • Proven technology; 35 years of experience in sun simulation
  • Proven track record; selected by leading PV test labs and manufacturers

We offer

  • World-class solar simulators with integrated climate chambers
  • Expert knowledge and advice
  • PV module testing at import locations



NREL installs the HPLS from Eternalsun Spire to further decrease PV module measurement uncertainty

NREL’s PV Cell and Module Performance group installs the Eternalsun Spire AAA+ High Performance Light Soaker (HPLS) to support its goal of offering the lowest possible measurement uncertainty

NREL PV calibration with solar simulators

What sets our products apart

  • 2 70ms

    Xenon Single Long Pulse up to 230ms

    Accurately measure high capacitive PV modules such as PERC, HIT, IBC etc., without the need for software correction

  • 300-1200nm spectum, SPC >99%

    Simulated light with wavelengths between 300 and 1200nm and high spectral Coverage (SPC) according to IEC 60904-9 ed. 3 ensures true Pmax output of high-efficiency technologies

  • High Micro uniformity over 2,6 x 1,4 m area

    Micro (high resolution) uniformity is important to accurately test half-cut and shingled PV modules

  • Superior repeatability and reproducibility

    Repeatability ≤ 0.15% and reproducibility ≤0.20% for long-term simulator stability and “matching” of simulators across multiple plant locations

  • High thoughput

    Best form factor for inline automation interfaces combined with a high throughput of 20-second typical cycle time

  • Extremely uniform temperature control (for labs)

    Temperature range from 15 to 75 °C with ±1°C temperature uniformity on 9 sensors to perform temperature coefficients and energy rating tests

Do you want to learn more? Contact us!

Eternalsun Spire is a leading manufacturer of solar simulators for measuring the performance and reliability of PV modules.

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