SOPHIE – Spektrum-optimierte Photochemie zur Erweiterung von PVT bzw. PV-PEC Systemen für intelligente Energieproduktion

The demand for green hydrogen, which is currently less than 1 Mt/a, is expected to rise to up to 400 Mt/a by
2050 (IEA Net Zero Scenario). To meet this demand for green fuels and, in the future, chemicals, widely
available raw materials are required. The direct use of sunlight in photochemical processes to produce
hydrogen, fuels, and chemicals from water (including wastewater) could become a key technology of the future.
A crucial challenge in this context is area efficiency, ensuring that the required solar surfaces are used as
effectively as possible. While PV technology can already convert more than 20% of sunlight into electricity,
direct photochemical processes (including photoelectrochemistry) typically achieve less than 10% (in some
cases up to 15–20%). To make a relevant contribution to area-efficient energy production, these efficiencies
must be significantly increased. One approach is not only to further develop the processes but also to integrate
them into combined systems.
The SOPHIE project aims to develop a hybrid multi-product collector that optimally utilizes the entire solar
spectrum. Through innovative spectral splitting, three energy conversion processes are simultaneously
integrated:

1. Photoelectrochemical (PEC) hydrogen production (‹700 nm)
2. Photovoltaic (PV) power generation (700–1100 nm)
3. Solar thermal (ST) heat utilization (›1100 nm)
   

This approach could achieve “solar-to-multiproduct” efficiencies of › 75% and enable area-effective solar
energy production.
SOPHIE builds on existing expertise in PV, PEC, and concentrated ST technology (including their
combinations, such as PVT) and integrates these technologies into a highly efficient hybrid multi-product solar
collector. The innovative aspects include a spectral splitting method for targeted light distribution, further
development of the combined technologies, as well as the design, implementation, and proof-of-concept of an
initial prototype at the laboratory scale (TRL › 5).
The proof-of-concept is based on hydrogen production, with the collector also being adaptable for industrial
parks with CO₂ sources for CCU processes, depending on location and local needs. Thus, SOPHIE makes a
significant contribution to future decentralized and regional solar energy and chemical production and supply,
thereby playing an essential role in the energy transition.