Economist Timothy Taylor has an interesting blog post about the environmentalist dream to “electrify everything.” His entire post is worth your time, but there’s one element that’s worth emphasizing.
Wind and solar power face what’s called “the intermittency problem.” Andrew Stuttaford concisely summarizes the problem as follows: “The sun doesn’t always shine, and the wind doesn’t always blow.” A natural-gas, coal, or nuclear plant can run at any time so long as it has fuel, a factor humans can control, or at the very least, can control more than they can control the weather.
Taylor points to a Brookings Institution study that includes this graph:
Taylor writes:
The dashed blue line in the figure shows month to month consumption of electricity in 2022, compared to January. Notice that demand for electricity drops off a little in January and February, then rises in the summer with the demand for air-conditioning, and then drops off again in the fall. This consumption pattern is more-or-less matched by fluctuations in solar power, which is at its lowest in the shorter, colder days of January, and much higher by mid-summer. (It’s important to be clear that the graph shows percentage changes compared to January, not quantities. Thus, the graph does not say that solar produces a high enough quantity to cover all consumption!) Wind power drops off in the summer. Different parts of the country are more likely to use either electricity from natural gas or from coal, which helps to explain the seasonal movements in these electricity sources.
The intermittency problem is not just about changes in the weather. It’s also a cyclical pattern. Natural gas, coal, and nuclear can be adjusted to match consumption patterns. Wind power is especially ill-suited for electricity needs because it generates less power in the summer when electricity demand is highest. The solar curve has more of the right shape, but it peaks before consumption does, and there’s no way to store that electricity to use later on a large scale.
According to the Energy Information Administration, the U.S. is banking on solar generation to provide the bulk of the country’s new electricity-consumption needs by 2050. The intermittency problem will become a more pressing concern as the government-backed “energy transition” continues.