NBC emails about “How California found itself with an unexpected surplus of clean energy that's now going to waste” and says “As California works toward its ambitious clean energy vision, an almost counterintuitive challenge has emerged: The state is, at times, generating more solar energy than it can handle.” But what could be more probable, if governments plunge recklessly into subsidizing forms of energy that are not efficient, including because they tend to produce power at the wrong time of day, that an expensive glut would develop? Have the journalists studied no more economics or engineering than the politicians?

So it would seem. Although to try to be positive, the fact that such a story has now been run suggests that as the rubber misses the road to Net Zero, practical questions are finally commanding some attention. It even mentions the “duck curve”.

The what, you may ask? Especially if you are a solar power enthusiast. But it’s actually a well-known engineering phenomenon: the shape of the daily demand curve for power net of renewables, in California as elsewhere, remarkably resembles a duck seen from the side facing right. The tail comes in high and flat between midnight and sunrise, because people use energy for things like heating or air conditioning while they sleep and the sun don’t shine and the wind don’t blow. Then there’s a precipitous drop as both begin to happen, and the more such “clean” power a government invests in, the more it drives the conventional baseload demand down to the duck’s belly, now in California approaching zero. But guess what?

Right. Mr. Sun sets every day, and the wind tends to die down, and it happens just as people go from using a lot of energy to using even more around dinner time. So the steep neck leads to the top-of-head bump around 8:00 p.m. which then tapers off down to the beak around midnight. Quack and repeat.

Is all this stuff innocent? Heck no. It’s bad enough that the effect of installing all this wind and solar is not to reduce your reliance on gas and oil but to require that you have two side-by-side energy systems, the trendy expensive one that produces power at the wrong time and the reliable affordable one you hate. What makes it worse is that you often get not just enough power to stand down the conventional kind, but more than you know what to do with.

As NBC notes:

“‘We get into certain times of the year, in the springtime particularly, when the demand for electricity isn’t that high yet, and we have quite a bit of solar production where, under certain conditions, we actually have more than California can actually use,’ said Elliot Mainzer, the CEO of California’s Independent System Operator, which manages 80% of the state’s electricity flow.”

They manage to sell some of it. But unfortunately ducks are not confined to California and therefore:

“According to Independent System Operator data, in recent years, the amount of renewable energy curtailed, or wasted, has skyrocketed from both oversupply and so-called congestion, when there’s more electricity than the transmission lines in some areas can handle. So far this year, the state has lost out on nearly 2.6 million megawatt-hours of renewable energy – most of it solar – more than enough to power all the homes in San Francisco for a year.”

Brutal. Now they’re dreaming of more transmission lines to try to export the problem further afield, and vast piles of batteries to store it during the day and release it at night without exploding.

For our part, instead of being amazed that they didn’t see it coming, after a lifetime of watching politicians not see consequences coming from the crucial truth that “incentives matter”, or for that matter the thing where the weather is milder in the spring, we find ourselves relieved that someone noticed it after it happened. These days, it constitutes progress.