Yes, it's a kind of hydroelectric power which uses off-peak power to pump water (as a source of gravitational energy) from a lower to a higher reservoir. You can say "pumped-storage hydroelectricity", or just "pumped-storage".

"Una central hidroeléctrica de bombeo es un tipo especial de central hidroeléctrica que tiene dos embalses. El agua contenida en el embalse situado en el nivel más bajo —embalse inferior—, es bombeada durante las horas de menor demanda eléctrica al depósito situado en la cota más alta —embalse superior—, con el fin de turbinarla, posteriormente, para generar electricidad en las horas de mayor consumo eléctrico."
http://www.unesa.es/sector-electrico/funcionamiento-de-las-c...

"Pumped-storage hydroelectricity (PSH) is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power."
http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

"Pumped storage plants
Pumped storage is the economically and environmentally most developed form of storing energy during base-load phases while making this energy available to the grid for peaking supply needs and system regulation. This has been done by Voith since this technology was invented. "
http://www.voith.com/en/products-services/hydro-power/pumped...