Renewable Energy
Known sources of energy are limited, or their use entails difficulties for the environment. To find answers to these challenges, scientists can use the X-ray flashes of the European XFEL to study processes occurring in solar cells or fuel cells. They can also use them to find new solutions such as artificial photosynthesis.
The Sun delivers enormous amounts of energy to Earth. However, clean, economic, and reliable conversion of this abundant energy is a challenging task.
The direct use of solar energy to generate electrical power (photovoltaic devices) or heat (photothermal devices) requires energy storage, as the production cycle—up during the day, down at night; up on clear days, down on rainy ones; more during summer, less during winter—does not match the consumption cycle. Energy storage is expensive and not very efficient, which limits photovoltaic and photothermal solutions.
In an effort to solve these problems, scientists are trying to optimise processes, that use sunlight to produce fuels that can be stored and transported, inspired by nature’s photosynthetic process in plants. 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, this process could be mimicked by reacting the hydrogen released from water with carbon dioxide to produce methanol or methane, which can be used as fuels.
The ability of FELs to reveal 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 exciting 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.