The manager of California's power grid said Wednesday that below-average hydroelectricity production could mean reduced supplies for consumers during high-demand periods this summer.
The California Independent System Operator's annual summer assessment predicts supplies could dip during peak evening hours on hot days when solar power dissipates and people get home from work and turn on air conditioning.
Cal-ISO said 2018 hydroelectric production will be down 1,300 megawatts by late summer compared to the above-normal production during a wet 2017. That's because snowpack water content was just 51 percent of average as of April 2, according to the state Department of Water Resources.
Peak summer demand is projected to be 46,625 megawatts under normal conditions. Last year's peak load was 50,116 megawatts on September 1, 2017.
The analysis found a 50-percent probability that for at least one hour this summer officials will need to declare a Stage 2 Emergency, which has not been implemented since 2007. A Stage 2 Emergency requires Cal-ISO intervention in the market, such as ordering power plants online to meet surging demand.
There's an extremely low probability officials will be forced to initiate rotating power outages, the report said.
Officials warned consumers to expect so-called "flex alerts," voluntary calls to reduce power use.
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Natural gas limitations due to storage facility and pipeline outages could add to the summer reliability concerns in Southern California, the report said.
Cal-ISO's annual summer assessment uses historical temperatures ranging from normal to extreme and demand data along with current power plant availability to build out 2,000 scenarios to calculate the probabilities of results for each hour of the day.
