Thoughts on the Required Power Storage in California

by George Harvey

California utilities are about to be required to store power from intermittent and variable sources. The rule will make them invest in at least 1.3 GW of storage.

Actually, 1.3 GW of storage is not much problem. A 1 GW storage plant was built in Massachusetts forty years ago and is still making money. It is the Northfield Mountain (NM) pumped storage plant.

NM was built in the early 1970s, just at the same time the Vermont Yankee (VY) nuclear facility, twenty miles away, was about to be built. The two are very different. VY is 640 MW, a bit more than it was when it was built; NM is about 160% of that. VY has a lot of local opposition; NM is not really known about locally. VY can melt down; the closest NM can come to a meltdown is a spring snow melt on the surrounding hills.

VY has boxy structures that sit on the Connecticut River, looking like an industrial site. By contrast, NM has woods, trails for skiing and hiking, places to picnic, and a little museum to show how the site works. It looks like a park, and this is because it is a park. But when the energy is needed, it can produce 160% of what VY can. It takes 15 minutes to bring it online, so it is good for a rapid response. By contrast, VY takes a couple days.

When NM was built, there was no solar power, and there was practically no wind power on the grid. So why was a pumped storage facility built forty years ago? That is simple. It is because nuclear power, which was about to be produced at VY, and coal power, which the country depended on, do not match grid demand well at all. In order to produce sufficient power to meet peak demands, they have to overproduce extravagantly at low demand times.

If you look at traditional baseload power, and do a little analysis, comparing it with a combination of solar and wind, I think you will find a very interesting thing. Traditional baseload power is not a better match to grid demand than solar and wind, if they are carefully matched.

All power sources are variable, and all power sources are intermittent. Nuclear plants, which are the most consistent source we have, have to shut down for weeks every couple years to refuel. When that happens, the next plant over picks up the load. By contrast, wind and solar seem a bit chaotic. That does not make them worse, because long transmission lines can connect distant parts of the country, and when 200 wind turbines fail to turn in California during a calm evening, the turbines in Texas and North Dakota can pick up the load (in 1996, the DOE estimated the maximum distance for cost-effective transmission was 4000 miles, and now we can install superconducting transmission lines.)

NM was the largest pumped storage plant in the world, when it was built. Now there are plants three times that size.

My advice to the utilities in California would be to construct a multiple of the amount of storage required. It can be done using half a dozen technologies I can name off the top of my head, and they can choose whatever they want from that group and more. With 10 or 20 GW, they can match production to demand. And that will stop price swings that send wholesale prices to a multiple of retail prices at some parts of the day and to negative prices at others. And THAT will save them money – scads of money.

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