Sustainable and efficient off-grid production of Hydrogen. Demo Project on-going in Spain In English R. Galvez, L. López, E. Oyarbide, L. García, P. Casero, E. Bueno: “Sustainable and efficient off-grid production of Hydrogen. Demo Project on-going in Spain”. Proceedings of the XVIII International Congress of the Mexican Hydrogen Society. Ciudad de México. Año 5, No. 5, Sept. 2018. ISSN-2448-7120