Known sources of energy are limited, or their use eintails difficulties for the environment. The find answers to these challenges, scientists can use the X-ray flashes of the European XFEL to study processes occuring in solar cells or fuel cells. They can also use them to analyse plasmas that could be exploited in future fusion reactors, or find new solutions such as artificial photosynthesis.

The sun delivers enormous amounts of energy to the earth. However, the clean, economic, and reliable conversion of this abundant energy is a challenging task.

Direct use of solar energy for generating electrical power (photovoltaic devices) or heat (photothermal devices) is confronted with the need to store energy, as the production cycle—up during daytime, down during the night; up on clear days, down on rainy ones; more during summer, less during winter—does not match the consumption cycle. The storage of energy is currently not very efficient and expensive, which limits the photovoltaic and photothermal approach (in analogy to wind power).

In effort to solve these problems, scientists are trying to optimize processes which would use sunlight energy to produce storable and transportable fuels, inspired by the nature photosynthetic process in plants, which uses sunlight energy. In plants, the energy of the sun is used to split water into oxygen and hydrogen, the latter of which is further split into a proton and an electron. Their recombination into hydrogen provides the energy to power subsequent reactions that are necessary for the life and growth of plants. Ideally, if one could mimic this process, one could use the hydrogen released from water to react with carbon dioxide and produce methanol or methane, which can be used as fuels.

The ability of FELs to follow the steps of a chemical cycle or reaction like in a slow-motion movie could help to better understand the efficient water-splitting reaction in plants and other natural or technical chemical processes. The unique capabilities of the European XFEL can significantly contribute to this exicting area of research. It can provide a basis for the application of an optimized photosynthetic process on an industrial scale, to generate hydrogen and liquid fuels from ingredients as cheap and abundant as sunlight, water, carbon dioxide and some light metals.