“Solar fuel” is the pretty formula chosen by Al Weimer, a professor in the Department of Chemical and Biological Engineering at the University of Colorado, to talk about green hydrogen produced using solar energy. This method is called the “thermochemical” approach: It breaks down water into hydrogen and oxygen gas. Traditionally, this decomposition is carried out by electrolysis and requires a considerable energy expenditure. Nevertheless, the process makes it possible to produce hydrogen in quantities that until now had not been the case with the thermochemical method. Al Weimar and a team of researchers demonstrated this in an article published in the journal joule that it was possible to implement this well-known method at very high pressures, using materials based on ferrous aluminate – both abundant and inexpensive. His discovery allowed him to more than double his hydrogen production. A discovery that could pave the way for more efficient and commercially viable production of hydrogen, particularly useful in the transport and steel industries.