From coal to hydrogen Curiosity · Puertollano, Campo de Calatrava, Ciudad Real Image of Puertollano, not of the place itself. Coal mining began in Puertollano in 1873 and closed on 1 January 1976. The town then reinvented itself as a petrochemical hub and today is turning towards renewable energy and hydrogen research. Photo: Fabián Pedrero Gallego (CC BY 2.0) What to see and do in Puertollano