Impacts of California’s Five-Year (2012-2016) Drought on Hydroelectricity Generation

Published: April 26, 2017
Author: Peter Gleick
Pages: 16

impactThe severe five-year drought afflicting California between 2012 and 2016 was the driest and hottest in the instrumental record. Impacts of California’s Five-Year (2012-2016) Drought on Hydroelectricity Generation examines the costs to California of lost hydroelectricity during the drought, which stretched from October 2011 to the end of September 2016 (the official California “water year” runs from October 1 to September 30).

Under normal conditions, electricity for the state’s millions of users is produced from a blend of many sources, with natural gas and hydropower being the top two. During the drought, reductions to state river flows that power hundreds of hydropower stations meant that natural gas became a more prominent player in the mix. This was an expensive change.

According to the report, the five years of drought led to an increase in electricity costs of approximately $2.45 billion. The additional combustion of fossil fuels for electric generation led to a 10 percent increase in the release of carbon dioxide from California power plants.

In addition, the report notes that the ability to expand California’s hydroelectric capacity is limited, as there are few undammed rivers, little unallocated water, and growing environmental, economic, and political constraints to adding new hydropower capacity. In an average year, hydropower provides 18% of the state’s electricity needs.

Comparatively, during the five-year period from October 2011 through the end of September 2016, hydropower generation averaged 10.5% of total electricity generation. In 2015, the driest year, hydropower provided less than seven percent of total electricity generated in-state, while in 2016, an increase in precipitation increased hydropower generation to around 12 percent.

Read the Full Report here.