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California plans for an energy future without San Onofre's nuclear power

Evening sets on the San Onofre atomic power plant December 6, 2004 in northern San Diego County, south of San Clemente, California.
David McNew/Getty Images
Evening sets on the San Onofre atomic power plant December 6, 2004 in northern San Diego County, south of San Clemente, California.

Tuesday the federal Nuclear Regulatory Commission plans a public meeting in Dana Point to discuss the future of the San Onofre nuclear plant.

It used to power almost a million-and-a-half Southern California homes. “Used to” because it hasn't functioned since it leaked a small amount of radioactive steam last January.

There’s a possibility that its operator, Southern California Edison, will scale back the San Onofre plant – or maybe will never power it up again. What does that mean for our energy supply?

That’s something the people who work at Cal-ISO are considering right now.

“What we do is plan for the worst. We do that every day,” Cal-ISO spokesman Steven Greenlee says.

RELATED: San Onofre 101: FAQs about the troubled San Onofre nuclear plant

The California Independent System Operator
– or ISO – has no say in what happens to San Onofre, but it has a big stake in the decision because it manages the state’s power grid. For Cal-ISO, the worst-case scenario is permanently losing a power plant as big as San Onofre.

“Because then you see our margins on heavy demand days are stretched very thin,” Greenlee says.

In other words, on hot days when we crank up the air conditioner – without San Onofre, there just isn’t enough power in Southern California. That’s when Cal-ISO issues FLEX alerts.

San Onofre’s Voltage Support is Key

And as important as the thousands of megawatts San Onofre generates is the voltage support it provides to move power through California’s electrical grid.

“All electricity on a transmission line needs support from other electricity in order to keep moving. It’s kind of like what water pressure does for water in a hose, ” Greenlee explains.

This is why voltage support is important– because while Southern California has limited power it’s a different story up North.

“The California electric system is in a state of extreme surplus right now, ” says Matt Freedman, staff attorney at the ratepayer watchdog, The Utility Reform Network

“So on a statewide basis, there’s far more generating capacity than is needed to meet even peak demand requirements across the state,” says Freedman.

To get that power north to south you need transmission lines and…voltage support.

Cal-ISO recently released its proposal for what to do next summer if San Onofre is still shut down.

Topping its list of recommendations is converting part of a natural gas-powered plant at Huntington Beach into providing voltage support.

This summer that same plant was used as a power-producing substitute for San Onofre. So why can’t that keep happening? Its air emission credits are about to expire.

“What we face is a tradeoff”

Take away nuclear and you have to replace it with something else. Right now, that something is natural gas or coal, says Per Peterson, who teaches nuclear engineering at UC Berkeley.

“Realistically, what we face is a tradeoff between using the nuclear power infrastructure that we have and producing electricity using natural gas,” Peterson says. “We need to recognize if we do shut these [nuclear] plants down, there’s an opportunity cost because it slows down the rate at which we can reduce our reliance on fossil fuels.”

Peterson says wind, solar and other forms of alternative energy just aren’t far enough along yet to provide all the megawatts needed to satisfy all our energy needs.

He says Southern California Edison’s proposal to re-start San Onofre with only one generator operating at 70% capacity is probably still cost effective, even though the plant would likely generate only about one-third the power it did before.

“Electricity costs in Southern California and California in general are quite high relative to production costs for production costs for nuclear power,” Peterson says. “So, the cost of operating the plant will still likely be lower than the revenue that one would generate from the sale of the electricity.”

Edison officials have been vague about its cost benefit analysis for San Onofre; instead, they emphasize that safety is the company's priority.

“We consider the utilization of any installed asset at a safe level to be cost effective,” Edison senior vice president and chief nuclear officer Pete Dietrich said last week. “It’s important to us and to our customers that an asset that’s able to be utilized safely is utilized to support the electricity needs of our customers and the people that live around that plan.”

Many people agree: Supporting those electricity needs would be much harder without San Onofre.