Climate Change Effects on Optimal High-Elevation Hydropower Generation in Sierra Nevada, California

Climate warming is expected to shift the runoff peak from spring to winter in California as a result of the reduction in snowpack. The Sierra's high-elevation system supplies roughly 74 percent of California's in-state hydropower supply and is composed of more than 150 power plants with relatively small reservoirs associated with them. Such low capacity reservoirs have been designed to take advantage of snowpack, the natural reservoir. With climate warming, the adaptability of the high-elevation hydropower system is in question as a shift in runoff peak can have important effects on generation and its economic value. A non-linear optimization model employing historic hourly energy prices is used to explore energy generation of 137 hydropower plants in California's Sierra Nevada mountains for three climate warming scenarios (dry warming, wet warming, and warming only) over 15 years, spanning dry, wet and average hydrologic conditions. These results are compared to the historic generation to investigate the adaptability of Sierra's high-elevation hydropower system to climate warming.