The long view of the water/energy nexus: Hydropower’s first century in the U.S.A.

This paper offers a historical overview of the first century of hydropower in the US from today’s perspective of the water/energy nexus. Hydropower emerged as a technology in the 1880s and its development expanded until large dam building ended in the US in the 1970s-1980s. I summarize the century from the two different angles of the water sector and the electric power sector, as the roles and strategic importance of hydropower changed dramatically in the two sectors, in the parallel histories of water development and electric power development. The paper emphasizes the electricity side of the hydropower story because the water and environmental aspects are more widely known. During the first 50 years, hydropower dams were far more important to the electric power sector than they were to the water sector. Dams were juicy economic prizes that were fought over by private and public power utilities, politicians and government officials, and other interest groups, and that were built into the core of regional power grids during their foundational decades. Control of hydropower symbolized the deeper political and economic conflicts between public and private interests in the power sector, with hydropower becoming strongly identified with public power. In both sectors, there was a major turning point in the 1930s because of the growth and intervention of the Federal government in the New Deal. The earlier trends reversed and over the next 50 years hydropower became essential in the water sector - scaling up rapidly as the critical factor in paying for Federal multi-purpose water projects - and secondary in the power sector (with regional exceptions). In the power sector, hydropower’s trajectory after the 1930s was paradoxical. It boomed in absolute terms, quadrupling in generating capacity as Federal agencies built hundreds of large dams, but hydropower’s relative importance in the power sector declined steadily as the rest of the sector grew even faster. The half-century of hydropower’s greatest expansion ended by its taking a smaller role in the overall power grid. Over the long run, the dynamics of the energy sector have dominated the water sector, a lesson that may apply to other examples of the water/energy nexus in the US and abroad.