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

The severe hydrological drought afflicting California between 2012 and 2016 has ended, with an extremely wet winter beginning in October 2016. That five-year period was the driest and hottest in the instrumental record going back to the late 1800s. Impacts on communities, ecosystems, farmers, and the economy were widespread but have been unevenly distributed. The Pacific Institute has regularly analyzed the consequences of California droughts, beginning with comprehensive assessments of the 1987-1992 drought (Gleick and Nash 1991, Nash 1993), the 2007-2009 drought (Christian-Smith et al. 2011), and this most recent drought (Cooley et al. 2015, Gleick 2015, Cooley et al. 2016, Feinstein et al. 2017).

This analysis is the third assessment of the impacts of the drought on hydropower production and greenhouse gas emissions from California’s energy sector (Gleick 2015, Gleick 2016). This analysis finds that during the five years ending September 30, 2016 (the end of the 2016 “water year”), hydropower generation was substantially below average, and the associated economic cost to California ratepayers was approximately $2.45 billion dollars. The additional combustion of fossil fuels for electricity generation also led to a 10 percent increase in carbon dioxide emissions from California’s in-state power plants (CARB 2015) along with increased emissions of other pollutants.