The report illustrates the main results of the “Solar Electricity” project. The research activities were carried out on topics related to the main stages of the concentrator photovoltaic technology chain, which can be schematically divided into aspects relating to the development of triple-junction cells, concentrator photovoltaic modules and systems, and the collection and management of direct solar radiation data.
The activity started with an updated analysis of the development prospects of concentrated photovoltaic technology and its market, both at a global level and, in particular, in our country. The results of the research into optimizing both the growth of triple-junction cells with a conversion efficiency of more than 36% and the associated post-growth processes required to produce the complete device are then presented, along with the activities of developing the techniques and instrumentation at the RSE laboratories required for their characterization. This is followed by a description of activities relating to innovative coatings, both nano-structured antireflective coatings, prototypes of which have been created to improve the absorption of radiation in the cells, and anti-fouling coatings for the glass of photovoltaic modules.
One of the main research products of the three-year project is the new prototype of RSE’s mirror photovoltaic modules, which integrate both the optical focuser and the solar tracking sensor developed in RSE’s research and produced using almost exclusively Italian technology: the modules, equipped with 32 solar cells, have a high efficiency (up to 31.5%) and a high solar concentration factor (>840 suns), which place them close to the upper limit of the high range of concentrator photovoltaic modules internationally.
The experimental concentration photovoltaic system is then presented, built and installed in the RSE Test Facility, where the modules have been characterized in real operating conditions. Finally, we report on the research activity related to the collection and management of data on direct normal irradiance (DNI) in Italy, provided by different sites belonging to a national consortium coordinated by RSE.