Another tight summer seen in Southern Calif. without San Onofre

The California ISO sees another tight power supply situation on the horizon as it faces the prospect of a second consecutive summer without San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 available.

Southern California could see reserve margins shrink to 6% during times of peak demand, the ISO said in a 72-page assessment issued May 6.

The two units, majority owned and operated by Edison International (NYSE:EIX) subsidiary Southern California Edison (SCE), provide 2,200 MW when running at full capacity. Both units, however, have been offline since January 2012. SCE is seeking NRC approval to restart Unit 2 at 70% power but there appears little chance that the unit could resume operation by the company’s June 1 goal.

When contacted May 6, a NRC spokesperson said there is currently no public hearing scheduled on San Onofre 2 restart.

“For the purpose of upcoming summer power projections, both SONGS units 2 and 3 are assumed to be unavailable, there is no supply coming from the Huntington Beach units 3 and 4 following retirement of the units, and a growing economy increases electricity peak demand by more than two percent as compared to last year,” the ISO said in a May 6 statement. “For these reasons, the summer assessment notes the reliability risks to southern Orange and San Diego counties are “marginally more challenging” this summer, but still within planning standards,” the ISO said.

From June 1, 2012 to April 1, 2013, a total of 2,502 MW has come on line and an additional 891 MW is expected to energize by June 1, 2013.

One of the largest new gas plants online for this year is the 500-MW Walnut Creek Energy complex developed by another Edison subsidiary, Edison Mission Energy. The plant is located in Industry, Calif.

New equipment and newly-installed transmission upgrades in the Los Angeles Basin should help carry imported power into the area.

However, the ISO cautions that heat waves complicated by higher than expected power plant outages in key areas of Southern California or transmission limitations triggered by wildfires or other reasons could challenge grid reliability, especially in the areas affected by the SONGS outage.

“We ask consumers to watch for Flex Alerts on TV and radio and conserve electricity to ensure enough power for everyone,” said ISO President and CEO Steve Berberich. “Californians can do their part to help relieve the stress on the system by reducing their electricity use during the afternoon peak created by air conditioning. We thank them in advance for responding,” Berberich said.

Margins are tight; hydro output down

The drought this year will limit typical hydroelectricity levels by more than 1,000 MW, the ISO said.

Operating reserve margins could narrow from about 20% down to 7% in Northern California during extreme conditions, but above the level that puts customers at risk of power outages. In Southern California, the cushion could drop to 6% during high peak demand, the ISO said.

Generation in the ISO balancing authority is primarily fueled by natural gas (62.9%), followed by 18.3% renewables portfolio standard (RPS) resources, 13.6% large hydro, 3.8% nuclear excluding SONGS units and a small amount of oil and coal.

The system-wide peak electric demand is expected to reach 47,413 MW during summer 2013, which is 738 MW more than the actual peak of 46,675 MW in 2012. The all-time record peak demand was 50,270 MW in 2006.

The average generation outages in 2012 were higher than in 2011, with a significant contribution being the SONGS outages. ISO average generation outage from June 2012 to September 2012 was 8,220 MW or 2,160 MW higher than that in 2011.

Significant amounts of new renewable generation has reached commercial operation and this trend is expected to continue as new renewable generation comes online to meet the state’s 33% renewables portfolio standard (RPS), the Cal ISO said. A certain amount of flexible and fast responding resources will need to be maintained on the system to ensure the success of the 33% RPS goal.

“A noteworthy challenge in this area will be the roughly 10,832 MW of natural gas fired capacity subject to the once-through-cooling regulation, which will require coastal power plants that use ocean water for cooling to be retired, retrofitted or repowered,” in the next few years, the Cal ISO said.

About Wayne Barber 4201 Articles
Wayne Barber, Chief Analyst for the GenerationHub, has been covering power generation, energy and natural resources issues at national publications for more than 20 years. Prior to joining PennWell he was editor of Generation Markets Week at SNL Financial for nine years. He has also worked as a business journalist at both McGraw-Hill and Financial Times Energy. Wayne also worked as a newspaper reporter for several years. During his career has visited nuclear reactors and coal mines as well as coal and natural gas power plants. Wayne can be reached at