The study of the Irati hydroelectric company aims to show some of the business strategies behind the first stages of the development of electricity in Spain and, in turn, pose new questions regarding the factors and conditioning elements of the country's regional industrialization processes. In fact, this firm represents one of the many possibilities electricity brought to non-industrialized Spanish regions at the start of the 20th century. The electricity generated by its falls explains the creation of Spain's largest integrated industrial complex built up around the initial processing of timber (saw-mills and chemical distilling) and its commercialization (railways), along with the sale of its energy surpluses on the most important market in the region of Navarre. Furthermore, the analysis of this latter activity allows us to offer an explanatory model that is both an alternative and a complement to the classical model —that provided by the largest firms—concerning the progressive incorporation of the traditional electrical markets into the integrated markets of the major Spanish companies.