Solar energy utilisation: Current status and roll-out potential

To meet the well-known energy transition challenge, a rapid shift from fossil fuels to the broader exploitation of renewable energy sources is needed; solar energy represents the most abundant and readily available resource amongst the renewable energy sources. This vision paper aims at shedding light on the current knowledge and emerging pathways for solar energy utilisation. Specifically, after a general introduction and a brief overview of the current knowledge, open issues are discussed regarding photovoltaic/thermal (PV/T) collectors, building integrated photovoltaic/thermal (BIPV/T) systems, concentrating solar power plants, solar thermochemistry, solar-driven water distillation, and solar thermal energy storage technologies. Subsequentially, this vision article defines key fundamental challenges that need to be addressed for these technologies to play a significant role in future sustainable energy systems. The identified challenges include developing new materials, enhanced performance, accelerated system installation and improved manufacturing processes, combining solar energy with other clean energy production and storage systems, and integrating solar energy utilisation with local energy utilisation patterns.