Sometimes a duck can tell us a lot about renewable energy.
Where are we going? To California’s solar power problems.
The Duck Curve
It’s pretty logical. During the evening we need more electricity than at noon. At home, preparing dinner and using the dishwasher, for AC or heat, for lights, our power use spikes from 6 to 10 pm.
That means the solar power California generates at noon needs to increase for the next 10 hours. So far, it cannot. As a result, California needs an alternative power source. The choices? Nuclear, natural gas, coal. Mixed solar, wind and hydro are also a possibility as are batteries or some form of storage.
This takes us to a catch 22.
As we improve our solar generating capability, we reduce what we will use from a back-up. But by generating more renewable energy, we make the problem worse. Sort of like the understudy in a play, an alternative source of electrification has to be there 24/7. But, when we demand it less, that back-up becomes less financially viable and potentially more expensive.
I feel as though I am taking us in circles but you see the problem. On the duck curve below, the problem lies where we have to ramp up along the duck’s neck. To avoid an outage, that ramp need has to be satisfied by a power plant ready to provide peak power.

Our Bottom Line: Thinking at the Margin
Economists like to say that rarely is a decision all or nothing. Instead, at the margin, we decide how much extra. For renewable energy, it is all about the margin. We are not just doing a cost comparison between renewables and more traditional energy sources. Instead, we have to recognize the cost of a very expensive “understudy” waiting to add whatever power renewables lack.
The problem is especially tough to solve because no one wants outages and no one wants higher electric bills. What is a politician to do?
My sources and more…Thanks to NY Times journalist Eduardo Porter for introducing me to the Duck Curve. From there, I discovered an excellent discussion at Judith Curry’s environment blog and media coverage at Bloomberg and the LA Times.