WINCOST is proposing and ambitious research programme centred on the development of renewable energy systems based on wide band gap (1.5 eV – 2.5 eV) chalcogenide semiconductor technologies. The project includes both new generation photovoltaic systems and new solar energy storage concepts based on more efficient photo-electrochemical systems. The development of efficient systems based on thin film technologies with wide band film to absorb chalcogenide is fundamental for the development of new generations of different types of solutions including: i) new and very high efficiency solutions based on the integration of mature crystalline silicon technologies with low cost thin film (combining the potential of silicon for obtaining high efficiency values with the cost-reduction potential of chalcogenide technologies); ii) new semi-transparent solutions for solar glass and photovoltaic panels; and iii) new solutions for obtaining solar hydrogen and photo-batteries. The project features an extensive research team made up of physicists, chemists and engineers that combines two IREC research groups together with researchers from the University of Barcelona and the Universidad Autónoma de Madrid and is coordinated by the Solar Energy Materials and Systems Group at the IREC. The project will help to make significant progress in the development of wide band chalcogenide semiconductor technologies, which is currently at an incipient stage, and includes both chalcopyrite based technologies (Cu(In,Ga)(S,Se)2 compounds) that are compatible with processes that have already been established on an industrial scale, such as solutions based on emerging technologies like kesterites (Cu2ZnSn(S,Se)4 compounds) and their alloys, which avoid the use of critical materials and elements both in terms in availability and accessibility on the Earth’s crusts and in terms of their toxicity. The development of technologies that are free of such elements is especially relevant for ensuring their capacity for sustainable production on a mass scale and using industrial processes with a very small carbon footprint. This is fostering increasing interest among the international community in kesterite technologies, a field in which the WINCOST project’s research team are world leaders. This activity is part of a strategic priority to research photovoltaic technologies at the IREC in major synergy with the other leading research groups in the world that are active in this area. This major component of international cooperation has been boosted by IREC’s prominent role in the coordination of important projects on the European Union’s H2020 programme, such as STARCELL (www.starcell.eu), and forms part of a priority strategy in Europe to lead the way in technologies that enable mass production of electrical energy in a clean, sustainable and very low-cost manner, thus benefiting universal access to safe and sustainable energy based on the efficient use of the greatest source of renewable energy on the planet, namely sunlight.