During the half century since the end of the conflict of 1936–9, the question of energy requirements troubled the Spanish authorities on two separate occasions. Firstly, during the 1940s and the first half of the following decade, consumers – both domestic and industrial – suffered the combined effects of acute problems in securing adequate supplies of imported oil along with cuts in the electricity supply. On the second occasion, which resulted from OPEC's decision in 1973 to employ the oil weapon, the ailing dictatorship and its democratic successors were confronted almost overnight with the nation's perilous dependence on imported energy. Above all, as we have seen, Spain's rapid industrialisation in the period 1960–74 was heavily concentrated on the impressive expansion of the energy-intensive heavy goods sector. Carles Sudria, in a pioneering survey article on energy in Spain, distinguishes three distinct phases since the Civil War: war, autarky and energy shortages (1936–55), the age of oil (1955–73) and the subsequent energy crisis and its aftermath (Sudrià, 1987). Sudrià's periodisation will provide the framework for the rest of this chapter.

Bottlenecks to energy supply, 1939–55

By comparison with its advanced neighbours to the north, Spain, with its arrested industrial development and low level of urbanisation, consumed relatively limited amounts of energy per capita in the immediate post-civil-war years.

At the beginning of the Franco era, almost nine-tenths of Spain's energy consumption was coal-based. After a severe interruption to mining activities in Asturias, which traditionally accounted for approximately three-fifths of the domestic output, production returned to normality in 1939.