California ISO gears up for summer 2014

The California Independent System Operator (California ISO) released its 2014 summer assessment that shows the ISO system has adequate power supplies for meeting summer peak conditions across the state despite well below average hydroelectric supply.

Southern Orange and San Diego counties will be a focus of summer grid operations in the event that heat waves, unexpected power plant outages or wildfires threaten transmission lines and challenge reliability in the area affected by the closure of the San Onofre Nuclear Generating Station.

Under challenging conditions, ISO operators will count on customers participating in local demand response and conservation programs to reduce their power use when the ISO issues a Flex Alert through the media.

“We know it is an inconvenience, but if the ISO issues a Flex Alert asking for conservation it is because the grid is under a lot of stress and we need to immediately reduce power demand,” said ISO President and CEO Steve Berberich. “Voluntary conservation is better than people losing power when demand outstrips supply.”

While drought conditions will have little impact on supply availability in San Diego and Orange counties, the overall ISO system will have less hydroelectricity than last year. As of April 29, 2014, statewide precipitation was at 56 percent of average. Meanwhile, snowpack water content was at 20 percent of average for the date and reservoir storage was at 63 percent of average for the date.

The ISO expects to have 1,370 MW to 1,669 MW less of in-state hydro for summer 2014. Pacific Northwest hydro conditions are about normal and should help make up some for the low California hydro conditions.

Operating reserve margins for the ISO system are good for normal conditions at 24 percent, but it could fall to about 14 percent during extreme conditions, which still remain above the threshold that puts customers at risk of power outages, which is triggered when reserves drop to the 3 percent level.

The system-wide peak electric demand is expected to reach 47,351 MW during summer 2014, which is 646 MW more than 2013 weather normalized peak of 46,705 MW. The all-time record instantaneous peak demand was 50,270 MW in 2006.

Meanwhile, the ISO projects that 53,950 MW of power capacity will be available this summer, which is an increase of about 3,243 MW of new generation since last summer. About 68 percent of the new generation is from renewable resources. Renewables make up about 22 percent of the ISO resource mix, which is an increase of about 4 percent from summer 2013. The ISO set a new instantaneous production record for solar power of 4,475 MW on April 30, 2014. The instantaneous wind record occurred on April 12, 2014 with 4,769 MW generated. As of May 1, the ISO has about 15,126 MW of renewable resource capacity connected to the grid.

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The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at

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