Publication


Impacts of California’s Ongoing Drought: Hydroelectricity Generation 2015 Update

Published: February 2016
Authors: Peter Gleick
Pages: 10


Full Report

Overview

Hydropower and natural gas are the principal sources of electricity for California’s millions of users. But California’s hottest and driest drought in recorded history, from 2012 to 2016, shifted the sources of energy for electricity with adverse economic and environmental consequences. The prolonged period of extreme drought reduced the river flows powering hundreds of hydropower stations in the state. Natural gas replaced the lost hydroelectricity, at high cost to both consumers and the environment.

This report is a comprehensive assessment of the costs to California of lost hydroelectricity during the four years of drought from October 2011 to the end of September 2015 (the official California “water year” runs from October 1 to September 30).

Key Findings

Key findings:

  • The drought at the time of publishing is more severe than past droughts, and hydropower generation is at 10.5 percent of total electricity generation during the four-year period from October 2011 through September 2015, compared to 13 percent during the 2007-2009 drought and the 18 percent average in non-drought years. For the 2015 water year hydropower was especially low, providing less than 7 percent of total electricity generated in-state.
  • This analysis finds that during the four years ending September 30, 2015 (the end of the 2015 “water year”), the added economic cost to California ratepayers of reduced hydroelectricity production was approximately $2.0 billion.
  • In addition to the direct economic costs of replacing hydroelectricity generation, there are environmental costs associated with the additional combustion of natural gas, including increased air pollution in the form of nitrous oxides, volatile organic compounds, sulfur oxides, particulates, carbon monoxide (CO), and carbon dioxide – the principal greenhouse gas responsible for climatic change. Additional combustion of fossil fuels for electric generation led to a 10 percent increase in the release of carbon dioxide from California power plants.
  • As of early 2016, the drought continues: reservoir levels remain abnormally low, precipitation and especially Sierra Nevada snowpack are marginally above normal, and hydrogeneration is expected to continue to be below average until reservoirs refill. Thus, costs to California ratepayers and to the environment are expected to continue to mount.

Resources

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