By 2035, the share of photovoltaics (PV) could account for about 20 percent of the total electricity generated in Germany. To achieve this target, up to 100 billion euros would have to be invested in Germany. It must be remembered that every percent of measurement uncertainty in the efficiency of solar modules leads directly to a financial uncertainty of one billion euros. PTB has therefore set up the Competence Center for PV Metrology. This center offers a unique infrastructure of laboratory and free-field calibration procedures with the lowest measurement uncertainties worldwide. PTB is the only national metrology institute in Europe that is able to establish primary traceability of the measurement results for reference solar cells. About 50 percent of all systems installed worldwide are already traceable to PTB today.
Since 2019, the measurement infrastructure which is also needed to offer comprehensive calibrations for solar modules has been established at PTB. Such calibrations include the parameters that are necessary for a comprehensive, energy-based assessment of solar modules with regard to all influence quantities that are relevant to their output. Thereby, PTB’s focus is on the quantities which are difficult to determine, i.e.: the performance under standard test conditions; the angle dependence; the dependence on the spectrum; and the dependence of the solar module temperature on wind velocity. Among other facilities, an LED-based sun simulator is the most important facility of the Competence Center. With this tool, the behavior of solar modules with a size of up to 2 m × 1 m can be simulated under various irradiation conditions found in the environment. This means that the standard annual output of solar modules (according to the Energy Rating Standard series IEC 61853) can now be determined.