Bioenergy is controversial, especially since it competes with food production. But now scientists in Kassel are looking for environment-friendly alternatives. They are doing research on possibilities of using grass and leaves to generate bioenergy. So far, no method has been found to use them as fuel. But by means of a kind of washing procedure, the researchers have managed to convert plant residue into usable fuels. Soon, farmers and municipalities might be able to use green waste to create valuable fuels. Bioenergy protects the climate and helps ensure that valuable green areas in the country continue to be cultivated.