The drought in California is continuing to increase in severity, resulting in less hydropower and increased natural gas generation.
In January 2014, California's governor declared a state of drought emergency; as of September 30, 58% of the state was classified as experiencing exceptional drought, the most intense drought category.
Source: US Department of Agriculture Drought Monitor; National Drought Mitigation Center.
California's drought, which began in 2011, has resulted in a significant decline in hydropower generation. On average, hydropower accounted for 20% of California's in-state generation during the first six months of each year from 2004 to 2013.
During the first half of 2014, however, hydropower accounted for only 10% of California's total generation. Monthly hydropower generation in 2014 has fallen well below the 10-year range for each individual month.
Graph of California hydropower net generation. Source: US Energy Information Administration, Electric Power Monthly.
In California, natural gas-fired capacity is often used to help offset lower levels of generation from hydropower facilities. The chart below shows how this inverse relationship can work: when monthly hydropower generation dips under 10-year average levels, monthly natural gas generation often rises above its 10-year average in response.
Source: U.S. Energy Information Administration, Electric Power Monthly.
From January through June 2014, natural gas generation in California was 3% higher compared to the same period in 2013 and 16% higher compared to the January-June average from the previous 10 years.
Edited from source by Katie Woodward