Wednesday, October 28, 2015


What I Learned at Stanford This Weekend

At my 40th reunion this past weekend (man, do I feel old), I went to some short lectures by Stanford professors. One was by Prof. Jacobson, who thinks we can go full alternative energy in the US by 2050. Here is his The Solutions Project website.

I thought he was insane or at least insanely optimistic. Here is my single example of his insanity, although I could write a lot about what he said that was wrong. His plan is for about 35% plus of our electricity to be generated by wind and about 55% by solar mostly from photovoltaic panels. He is aware that the sun only shines part of the time and even when it's shining the weather sometimes makes its light virtually unusable by the panels. So there has to be a way to store the electricity for use when it's dark. He wisely avoids battery storage. But these were his solutions for storage of the electricity from these panels: 1) pumped hydroelectric; and, 2) ordinary hydroelectric. The first problem that jumped out at me was that ordinary hydroelectric is an alternative to photovoltaic not a form of storage of electricity, so that was a disappointing dodge. So let's talk about pumped storage.

You build two dams, one at an altitude higher than the other. Behind these dams will be enough water to fill one of the two lakes created by the dams. You build a hydroelectric power plant in the dam at the upper lake and you build a big pumping station between the two lakes. When the sun shines, you use the electricity from the panels to power the pumping station to lift the water out of the lower lake and put it in the higher lake. When the sun goes down, you let the water in the higher lake flow down through the turbine generators into the lower lake.

So there will be one lake's worth of water moving between two lake beds. There won't be any fish or much other life in the water alternately flowing through pumps or the blades of a turbine generator. Alternately the lakes will be muddy remnants of lakes awaiting, or in the process of, refilling. They'll take a lot of room in the environment and they won't be cheap. Oh, and you'll have to have adjacent significant areas of suitable lake sites at significantly different altitudes. That's not going to be easy to find on the Great Plains.

But it's the scale that makes it a fantasy. We'll probably use well more than two terawatt-hours (two trillion watt-hours) of electricity by 2050 (although the plan is to reduce through conservation and efficiency that power demand down to 1.8 terawatt-hours). Some of the solar power the professor envisions will be from the fields of mirrors used to reflect sunlight on a single tower and those don't need storage of electricity as the solar energy is stored in molten salts as heat. So I'm not 100% sure what percentage of the 55% of our entire energy needs will be theoretically supplied by photovoltaic panels but I'll use 40% for our calculations here. 40% of 1.8 terawatt-hours is .72 terawatt-hours. That's a lot. All of the normal hydroelectric dams in the United States only produces now .33 terawatt-hours. There are no pumped water storage systems supplying any real power at this time. So he envisions as possible and desirable going from 0 to .72 terawatt-hours of power generation in 35 years. All to avoid a theoretical few tenths of degrees of warming, to avoid it being a little bit nicer out, especially at night.

As I said, insane.

But, boy, were the people in the audience applauding the heck out of his lecture.

UPDATE: There is a pumped storage facility in California. Thanks for the tip, kind reader. And you don't have to build pumps and turbine generators, you can just build one set that is reversible. It takes four units of power, however, to create three from the pumped storage water flowing back downhill. Here is what you need to know about this plant. It's not storing solar power for use at night but is storing unused nuclear power at night for peak use later in the day. And they don't drain the two lakes dry using the water for power. Very wise. How the heck are we going to be able to scale up this 1.1 megawatt source into .72 terawatts?


PG&E already has a similar paired set of power plants.
Diablo Canyon Nuclear plant in Avila, California provides power at night to the Helms pumped storage project in the Sierra's for use to generate power in the afternoons for the San Joaquin Valley.

There is still the problem of scale... and environmental reviews, location...

Thanks. I'll look at your link. But this is not storage of solar power but realizing we use more electricity during the day than at night so they use the steady nuclear power to store for peak use during the day.
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