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PV Module Power Measurements

PV Module Performance Measurements | TÜV Rheinland

Proven performance with reliable power measurement

Manufacturers, investors, power plant operators and private users depend on precise and transparent power rating to ensure PV module performance expectations and protect return of investment. PV modules tested and certified through independent third-party calibration according to recognized international standards increase consumer confidence and strengthen brand image in competitive global markets.

We provide precise power measurement services according to IEC 60904 series standards as well as the unique “Power Controlled” test mark. In the in-house developed standard 2 PfG 1795, comprehensive requirements are set in order to verify the power rating of PV modules is precise and correct on an ongoing basis. With our Measurement Uncertainty Assessment service, we help module manufacturers identifying their rating tolerances. Our experts conduct state-of-the-art performance verification and reference module/pyranometer calibration to prove reliable functionality and optimal performance. We help qualify solar simulators for use in the production of PV modules and provide simulator manufacturers recognized certification of their simulator class. Our “Power Controlled” certification of PV modules is specifically designed to ensure accurate and trusted data sheet information on which consumers can rely.

Our international network of experts is ready to serve you with our extensive services portfolio from a single source at any time, anywhere in the world.

Verify the true power of your PV modules with precise performance measurement!

Precise and profitable with our power verification services

PV Module Power and Performance Measurements | TÜV Rheinland

Our power measurement services provide you results with the highest possible accuracy enabling you to significantly boost confidence in your product for a stronger customer trust. We support you in making sure your performance claims are realistic and reliable and we help you to reduce warranty compensation with precise labeling. We qualify and certify solar simulators to ensure minimal uncertainty. Our experts work with high precision equipment so that you can meet strict quality standards requiring established calibration protocols.

Our “Power Controlled” certification provides buyers of PV modules the transparency they need to drastically lower the cost of any imposed third-party verification testing.

We conduct precise Reference Module calibration, so that you are able to sell each watt for its true value at the appropriate price.

Measurement Uncertainty for Photovoltaic Modules (PV Modules)

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The power rating of photovoltaic (PV) modules is the most important factor influencing the determination of your module price.

Our PV module power measurement services portfolio

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Performance verification

We provide reliable verification of module performance in cases when achievement is under the labeled power rating and tolerance levels. We verify the efficiency of crystalline silicone and thin-film PV modules based on a precise determination of output under Standard Test Conditions (STC) as well as ascertain the aperture area relevant e.g. for world record efficiency measurements. Our verification measurements comply with applicable international standards. We maintain state-of-the-art laboratories with comprehensive high-tech measuring equipment. We implement qualified class AAA solar simulators and primary calibrated reference cells traceable to the World PV Scale (WPVS) to attain precise measurements at the lowest level of uncertainty.

Reference module calibration / pyranometer calibration

We conduct secondary calibration of reference PV modules as part of our comprehensive calibration and performance measurement services. Calibration is performed on customer-provided secondary modules according to the international IEC 60904-2 standard. With an international network of calibration experts, we are able to provide you the services you need from a single source at any time, anywhere in the world.

Solar simulator qualification (PV module manufacturer) / certification (Simulator manufacturer)

We provide comprehensive qualification of solar simulators for use in the production of PV modules and provide simulator manufacturers recognized certification. Our experts have served many customers around the world, providing reliable testing and precise results as well as verification, classification and certification. Measurements in the production line also allow PV module manufacturers to optimize existing systems to increase in-line power control accuracy.

Among our many projects, we have tested turn-key pulsed solar simulator systems which achieved Class A+/A+/A+ compliance for an irradiance range of 600 W/m² to 1200 W/m². These systems also complied with Class A/A/A+ for an irradiance range of 200 W/m² to 500 W/m².

Our testing determines that Class A+ or Class A requirements have been met in the following criteria:

  • spectral match
  • non-uniformity of irradiance
  • long-term temporal instability LTI

Our detailed simulator assessment in the factory allows module manufacturers to minimize their rating tolerances.

Power Controlled certification mark

The qualification procedure for the specification of credible electrical power ratings aims to converge manufacturers ratings with measurements from accredited laboratories such as ours. To achieve this goal, our experts apply the following measures:

  • Introduction/qualification of calibration and quality assurance procedures
  • Establishment of direct correlation of power measurements in the production line with national and international standards
  • Qualification of measurement equipment (e.g. solar simulator)
  • Regular calibrations and power measurements of PV modules from the production line at our accredited laboratory

These proven measures are used to ensure decreased uncertainty in the specification of overall production tolerances and establish consensus on the definition of credible power ratings.

Power Controlled certification process

Our Power Controlled certification process is broken into the following four tasks:

  • Task 1 – The introduction and precise calibration of suitable reference modules used for flasher calibration in the production line.
  • Task 2 – On-site measurement procedure assessment and classification measurements for each solar simulator in the production line.
  • Task 3 – Verification measurements performed in our accredited test laboratory on test samples randomly selected from each production line.
  • Task 4 – Follow-up Power Controlled certification procedures to include annual re-certification of reference modules (Task 1), annual re-qualification of solar simulators (Task 2) and the periodical verification of test samples (Task 3).

Tested modules are awarded certification if the average measuring discrepancy between the manufacturer and the testing laboratory remains below 2 %, and if the average discrepancy between power output measured in the laboratory and the maximum output power displayed on the type label is less than or equal to 1.5 %.

Golden modules for each PV module power class and design should be calibrated at least once per year to attain a calibration report or Power Controlled certification.

PV Modules Performance Measurements | TÜV Rheinland

Your trusted and accredited partner around the globe

As one of the most renowned laboratories in the world, we are the market leader in solar technology testing and certification. Our experts precisely assess all PV technologies and provide results of the highest accuracy. We issue optional reminders for expeditious scheduling of your re-calibration, -qualification, or –certification. Our interdisciplinary network of PV specialists conducts state-of-the-art services reflective of our internationally trusted and respected brand. We are ready to serve you from a single source at any time, anywhere.

Answers to some common questions

We answer your questions regarding PV module power measurement. Just a phone call away, our experts are standing by to provide you any additional information you may need.

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What uncertainty is there when measuring PV modules?

Uncertainty when measuring PV module power and performance depends on each technology. Spectral response measurement and high-precision equipment can produce measurements of +-1.5% accuracy. It is best to speak with an expert regarding your particular circumstance. We look forward to speaking with you.

Are there special requirements for some technologies?

Some technologies might require stabilization e.g. by light soaking prior to an accurate measurement.

How are bifacial PV modules measured?

We helped lay the foundation defining the so-called bifacial standard test conditions (BSTC), which can be used to support the IEC TS 60904-1-2 technical specification and the international IEC 60904-3 standard and establish supplementary requirements for the power rating and label verification of bifacial PV modules.

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Solar and Photovoltaic (PV) Services

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