Innovative stable inorganic tandem solar modules

By 2050, renewable energies will account for at least 60% of total energy consumption in many countries worldwide. According to the International Renewable Energy Agency (IRENA), the use of renewable energies must be expanded to all sectors. In this context, the EU-funded SITA project will investigate innovative concepts for tandem solar cells based on silicon heterojunctions and high bandgap. These two technologies have a strong competence base in Europe. The project will develop an innovative concept with a two-terminal approach that requires no additional cables or electronics and is made possible by recent developments in copper indium gallium selenide wide bandgap solar cells, which result in high efficiency. SITA will demonstrate the new modules under realistic outdoor conditions and deliver stable inorganic tandem solar modules with outstanding device efficiency.

Project objective

To meet the major challenge of transitioning the energy system to a minimum of 42% photovoltaic energy by 2050 (as predicted in an IRENA scenario), our proposed SITA project aims to explore innovative concepts for tandem solar cells based on two technologies with a strong competence base in Europe: silicon heterojunction (SHJ) and Cu(In,Ga)(Se,S)2 (CIGS) with high bandgap. A novel tandem concept with a 2-terminal (2T) approach is being developed that requires no additional cables or electronics and is enabled by recent and further developments in high bandgap CIGS devices, resulting in high efficiency (>18%). SITA will demonstrate the durability of the new modules under realistic outdoor conditions, delivering the next generation of stable inorganic tandem solar modules with outstanding device efficiency (>30%). SITA's technology builds on SHJ modules and increases their efficiency by a factor of 1.5 with only a slight increase in the use of the most expensive raw materials. This in turn leads to a significant reduction in area-related system costs of up to 25% per installed capacity and a corresponding reduction in the levelized cost of electricity (LCOE). The efficiencies of tandem junction modules have recently reached or even exceeded the Shockley-Queisser limit for single junction prototypes. SITA will address the remaining limitations in terms of stability, scalability, manufacturing costs, and environmental compatibility.

Start date: September 1, 2022

End date: August 31, 2025