Iberduero (IBEX 35: IBE) was a Spanish company, dedicated to the generation and distribution of electricity, founded in Bilbao in 1944, as a result of the merger of Hidroeléctrica Ibérica and Saltos del Duero.

[1] The origin of Iberduero is in the company Hidroeléctrica Ibérica, which was founded in Bilbao by the engineer Juan Urrutia Zulueta on July 19, 1901, with capital provided by the BBVA.

To this end, it also formed a 50/50 alliance with Electra de Viesgo in the creation of Nuclenor in 1957, which carried out the construction and start-up of the Garoña nuclear power plant in 1971.

Iberduero also undertook the construction of the Lemóniz nuclear power plant, which was paralyzed in 1982 when it became the target of the terrorist organization ETA, which attacked its facilities and murdered two of its engineers (José María Ryan and Ángel Pascual Múgica) and three workers.

[citation needed] In 1990, Iberduero and Hidroeléctrica Española (Hidrola, one of its main competitors) began negotiations aimed at a possible union of their interests, seeking an alliance that would balance the electricity market, which was 40% dominated by Endesa, the same percentage that would be reached by the merger of both companies.