Solar fuels can and should replace their fossil-based counterparts and leave established technologies and (combustion) processes as unchanged as possible. Due to their high energy density, there is no alternative for some areas, especially for CO2-neutral long-haul flights.
It would be even more important if solar energy could be stored for the long term and utilised seasonally in this way. In winter, the solar energy from the previous summer could then be utilised. The biggest challenge on this path is economic efficiency: it is still usually cheaper to exploit fossil fuels and the solar energy stored in them over millions of years than to process today's solar energy accordingly.
Research topics
Researchers at the German Aerospace Center (DLR) are investigating solar thermochemical processes in particular. These processes have the advantage that they feed the solar high-temperature heat energy directly into the endothermic synthesis processes and thus convert it directly into the chemical energy of the fuel. This generally opens up higher efficiency potentials than processes with several conversion steps, such as hydrogen electrolysis with photovoltaic electricity.
While Power-to-Liquid processes of this type are already applied at a large scale, solar-thermochemical methods are more complex and still under development. DLR has extensive research expertise in this field, concentrated at the Institute for Future Fuels.
The Institute of Solar Research is working on making solar radiation available in a suitable form for the respective chemical processes.