Editorial: Recent Progress in Photovoltaics, Part 1

Global solar electricity production in 2018 is around 600 TWh and it is estimated to reach 1000 TWh by 2020. Polycrystalline thin film solar cells such as CdTe and CIGS with an efficiency over 20% have been fabricated. Recently, a novel material, Perovskite, has demonstrated an efficiency higher than 20%, although it has some stability issues. The future of photovoltaics depends principally on solar cell efficiency, its cost and its stability. The costs of solar photovoltaic panels have come down to achieve close to grid parity. Since advances in the science and technology of photovoltaics are taking place at a fast pace, it is important to present the state of the art of Photovoltaics and its trends for the future. For this reason, Solar Energy will publish two special issues focused on “Recent Progress in Photovoltaics”. The Guest Editorial team is pleased to present the first issue as “Recent progress in Photovoltaics, Part 1”

PV Performance during Low Irradiance and Rainy Weather Conditions

With data made available by a photovoltaic (PV) test facility located on top of an office building of the Utrecht University the performance of ten PV modules during time periods of low irradiance and precipitation was analysed. Using values for direct irradiance by Bird’s SPCTRAL2 model and measured climatic conditions a weather classification system was designed in order to categorize time periods and make a comparison between rainy and non-rainy time periods possible. Results show that precipitation induces a blue shift in the solar spectrum increasing the short-circuit current (ISC) of the modules (a-Si and CdTe in particular). Furthermore it is shown that precipitation causes module temperature to drop resulting in an increase in open-circuit voltage (VOC) for all modules. In terms of the performance ratio (PR) it is shown that almost all modules perform better under rainy than under non-rainy weather conditions, but it is noted that incorrect measurements of module temperature most likely overestimate the PR for some of the investigated modules