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Power Conservation Needed If San Onofre Stays Offline

Nuclear Regulatory Commission
San Onofre Nuclear Generating Station
Power Conservation Needed If San Onofre Stays Offline
California's Independent System Operator is considering what steps to take to prepare for the possibility that San Onofre does not come back online before energy demand spikes this summer.

Get ready to conserve energy this summer. The San Onofre Nuclear Generating station that provides 20 percent of San Diego’s energy is currently offline, while federal regulators investigate weaknesses in tubes running through the steam generator.

Today, the agency that balances power supply and demand in California, the Independent System Operation or ISO, is looking at what to do if the nuclear power plant does not come back online in time for summer’s peak demands.


The ISO calculates the likelihood that demand for electric would exceed supply this summer is less than 1 percent, but only if the nuclear power station is operating normally. If both San Onofre’s Units 2 and 3 remain shut down (Unit 1 is no longer in service), the power-generating reserves of almost 30 percent in Southern California would drop, and the system would face what it calls "reliability issues.”

The strategies on the table right now are bringing back online units 3 and 4 at Huntington Beach that were recently retired, speeding up transmission line upgrades so that lines can carry heavier loads and aggressive conservation measures. That means asking consumers to conserve power.

Staff also mentioned they would be closely monitoring what's happening at the Sunrise Powerline. They said that line and some of the related reinforcements will provide some "desperately needed" help to manage operating flexibility.

Peak demand is predicted to be about 46,000 megawatts this summer, a little lower than last summer because of Moody’s Analytics' estimates of low economic recovery.

The ISO estimates it can save 1,000 megawatts of power by using Flex Alerts that ask consumers to conserve energy at times of peak demand.


When operating at capacity, San Onofre generates 2,200 megawatts of power, enough electricity to power 1.4 million homes

John Geesman, an attorney from the Alliance for Nuclear Responsibility, chided the board for not looking longer term at the consequences of losing the power generated at the nuclear power station. He said this summer may be a problem, but his concern is next summer and the summer after that if the power plant is not part of the energy mix.

The reports the ISO considered today also said the state’s snow pack is at one of the lowest levels in its history, even with recent storms. That reduces hydroelectric capacity for the state.