Per Capita Davis: The reliability of our power supply

This column is written fortnightly by John Mott-Smith, a member of Cool Davis, and is cross-posted from the Davis Enterprise

Back in February, I wrote a column about nuclear power and the trouble I was having balancing the risks against the benefits. Basically, is the benefit of energy generated without producing any greenhouse gas emissions worth the potential downsides of catastrophic meltdown and nuclear proliferation?

I’m still gathering information (thanks to all who sent in suggestions for reading) but I’ve developed a lean toward a non-nuclear future, though I haven’t yet fallen over completely to that side of the argument.

In the course of gathering facts, however, I keep coming across one of the arguments for nuclear power — that we need consistent, inexpensive, reliable sources of power, and who can argue with that?

Usually, this is in the context of nuclear meeting these criteria whereas solar and wind energy are more expensive and notably unreliable because some days the sun doesn’t shine and the wind doesn’t blow. This “intermittency” is a problem for the electrical grid in terms of matching supply with demand.

Is nuclear power reliable?

But what about the reliability of nuclear power? There used to be three nuclear power plants operating at San Onofre, just north of San Diego. One of the three was dismantled in 1992 rather than undergoing $125 million or so in upgrades and repairs. It now acts as a storage facility for spent fuel from the other two reactors. Or would, if the other two reactors were in fact operating. They have been off-line since Jan. 31, when it was discovered that tubes carrying radioactive water were decaying.

There’s no projected date for when the reactors might start up again. The 1.4 million homes that relied on the nuclear reactors for electricity now get that electricity from natural gas-fired power plants in Huntington Beach that had been retired. So, the “intermittency” of these reactors includes, to date, six full months of producing zero power.

It turns out that industry wide the expected down time for nuclear power plants is about 11 percent.

It turns out that industry wide the expected down time for nuclear power plants is about 11 percent. Coal plants are about the same — 12 percent. That’s a lot. It would take a pretty large number of days without sun or wind for renewables to equal those numbers. I did not find estimates for large-scale solar plants and their expected downtime, perhaps because so few have been built.

Arguably, “off-line” does not equal “intermittent.” If a big chunk of power generation is unavailable the utility can, as is the case with San Onofre, buy power from another source. Lack of sun or wind is more of a short-term intermittency. It does seem, however, that weather forecasting is getting better and is probably more reliable than forecasting when a nuclear plant will develop a problem requiring it to be taken off-line.

Fukushima impacts

And then there’s the case of the Fukushima Daiichi nuclear plant disaster in Japan. All 50 of the country’s nuclear reactors were shut down in the aftermath of the earthquake/tsunami in March 2011. Now, more than a year later, concerned that losing more than 30 percent of their generating capacity is having adverse effects on the economy, they are in the process of restarting just two reactors.

Economic concerns have not been persuasive to the estimated 170,000 protesters who gathered in central Tokyo to object. A study commissioned by the government apparently concluded that the Fukushima Daiichi reactors may initially have been damaged by the earthquake, damage that was then compounded by the tsunami, thereby calling into question the safety of all reactors in earthquake-prone Japan. The government and the owners of the Fukushima Daiichi reactors have proposed a clean-up plan that will take 40 years.

It would seem that “intermittency” is a problem for any large-scale energy source. We often hear, for example, that oil refineries need to be shut down for repairs or maintenance and that this disrupts the supply of gasoline. This is also likely to be the case for large-scale solar power plants. Even though most are proposed to be located in the desert where sun is abundant and fairly constant, there will inevitably be problems that need to be fixed that will require the plant to shut down for some period.

Perhaps small-scale “distributed” solar (e.g. rooftops, parking lots, etc.) is the way to go.

All these shut downs, whether nuclear, coal or solar, have a cost. The San Onofre plant closure already has cost upwards of $100 million, of which the cost of replacing the power from another source is about a third of the total. The issue of who pays — ratepayers or shareholders — will be discussed, but in any event it is quite possible, according to the experts, that it will not be cost-effective to re-open these two aging reactors.

David Freeman, the former head of SMUD, argues that Rancho Seco, a nuclear power plant that at one time produced half of that utility’s electricity, was shut down by the voters — with no blackouts or rate increases for customers — and the power was replaced largely by encouraging renewable energy and conservation.

Perhaps small-scale “distributed” solar (e.g. rooftops, parking lots, etc.) is the way to go.