CA Hydropower and Drought

 

The following is excerpted from the U.S. Energy InformationAgency Report on Western Power Markets:

The extended drought in California could cut the state’s summer electricity generation from hydropower nearly in half compared with normal precipitation conditions, according to a modeling and analysis by the U.S. Energy Information Administration (EIA). EIA projects that hydropower will produce 8% of California’s electricity generation in a drought year, compared with 15% under normal precipitation conditions.

EIA projects that the decrease in hydropower generation will lead to an 8% increase in California’s electricity generation from natural gas, a 6% increase in energy-related carbon dioxide (CO2) emissions in the state, and an average 5% increase in wholesale electricity prices throughout the West given the current system's configuration.

“California has a diverse electricity fuel mix and is highly interconnected with the regional electric grid, but our study shows that a significant decrease in hydropower generation this summer could lead to higher electricity prices, among other effects,” said EIA Administrator Joe DeCarolis.

Hydropower is typically the third-largest source of electricity in California, but electricity generation from hydropower is highly reliant on snowpack that forms in the winter season. California’s snowpack was above normal as of December 2021, but it was 40% below normal levels by April 1 of this year. By May 11, 2022 update the snowpack was at 22% of normal. 

Over the last decade, California has experienced more frequent and intense drought conditions, and is currently in its third year of drought. Droughts limit water use in general and reduces hydropower in particular. Current drought conditions in the state can have a significant impact on power markets throughout the West, different than in past years. California has been aggressively accelerating growth in solar and wind energy which are intermittent in generating capacity and have been relying more heavily on power purchased and imported from other states. That imported power now accounts for nearly one-third of California’s power supply. Thus, the drought in California will require the import of more power- increasing the wholesale price.

As California has shifted toward more solar and wind energy resources for electric power generation and away from natural gas power plants the mix of power generation and its characteristics has changed. Since 2015, 58% of steam turbine natural gas units have been retired, or 6,500 megawatts (MW). Solar capacity, on the other hand, has increased by 8,800 MW (157%) since 2015. The increase in intermittent renewable generating capacity and the decrease in dispatchable resources -whose generation can ramp up or down to meet changes in system needs- means that fewer conventional power plants within the state are available to meet the system's. Over the same period power use has grown making the entire system more brittle. To help mitigate this situation, California has added significant battery storage capacity, growing from 11 MW in 2015 to 2,300 MW at the beginning of 2022. Batteries can provide system support to meet rapid changes in load and generation when renewables generate more or less than expected, but still only for brief periods. Even with California’s battery capacity additions, however, the total share of dispatchable resources is lower in 2022 than it was in 2015.