European researchers seek standard to assess short-circuit current temperature of PV devices

The Joint Research Centre (JRC), which is the European Commission’s science and knowledge service, has announced that an unprecedented agreement has been found in measuring the temperature dependence of photovoltaics by a group of research institutes involved in the EURAMET ENG55 “PhotoClass” project. The initiative is aimed at investigating the characteristics of PV devices beyond their performance in standard test conditions, including measurements at varying irradiance and temperature levels.

According to the research, published on ScienceDirect, the relative temperature dependence of the short-circuit current of different PV devices has been measured through round-robin tests with three different methods by six European partner laboratories. The measurements include reference-cell size and full-size commercial crystalline silicon modules, as well as CIGS and GaAs devices. “The main outcome of this measurement exercise is a very good agreement of all the laboratories although completely different approaches were applied,” the authors of the paper wrote.

The methods used to measure the temperature dependence of the devices relied on either spectral responsivity measurements or I-V curve measurements, depending on the participating laboratory. Despite the use of these two different methods, the research team claims that its findings show, for the first time, complete agreement between all results within the stated measurement uncertainties. “Although based on these two completely different approaches, all the α_rel results showed satisfactory agreement with the weighted mean calculated for each device, even suggesting that in some cases a revision of the UCs stated by the laboratories should be considered because they seem to be rather conservative,” the paper notes.

The EURAMET ENG55 “PhotoClass” project has developed, among other things, a new classification system of PV devices based on their energy output under different climate zones, which led to the new standard IEC 61853.