Wind power is like Ginger Rogers. You know what I mean. It isn’t judged by the same standards as other kinds of electricity generation.
I’m speaking specifically of the reliability of, or variation in, wind over time. Many people live in places where they personally experience highly variable wind, or at least, think they do, so it is easy to assume that wind generators would be sometimes running on full, sometimes standing still, in a more or less random and unpredictable way, but this is not necessarily true. There are regions where wind is much more consistent than people might imagine, though of course it is always somewhat variable. In fact, a bigger problem with wind may be not so much the variation, but the fact that in some regions it is out of sync with energy demands. In some temperate zones, wind may be weak during the day but stronger at night when electricity demands are low (but this can vary from region to region, and seasonally; there are places where winds tend to come up during the day and calm down at night)
The thing is, we often hear about how wind varies and thus wind can’t make up more than a certain percentage of our energy production. But this statement, while probably partly true until much better batteries are invented, ignores two things: 1) other forms of electricity generation also vary; and 2) we may have to live, in the future, with variable amounts of electricity. Oh, and 3) we can probably fix this all with a DC smart grid, but I’ll leave that for another time.
Regarding this first point, let’s compare wind to nuclear. A nuclear power plant like the one nearest me gets turned off now and then to replace fuel rods. This is not too often, and in theory this is done on a highly predictable schedule, but it is still a large amount of variation. That power plant, I assume, at best goes from normal high capacity to zero capacity for a while then back to high capacity. While wind may vary unpredictably, investing the cost of one smallish nuclear power plant in one small nuke plant vs. dozens of wind farms distributed across a very large area of the Dakotas and Minnesota will get you less difference in variation over time than one might expect.
As I noted, this variation in generation by a nuclear power plant is very predictable, so it doesn’t really count as variation. Variation you know is going to happen can be planned for. Predictability is the problem. But, that happens too with nuclear power plants. Whenever there is a tornado warning at the aforementioned plant, it gets powered down. That is not predictable. All sorts of other things happen at nuke plants that cause them to be powered down to some extent as well.
The point here is simple: When considering alternative forms of energy generation, it is not fair to say “wind is unpredictable and variable” and leave it at that, because it is not the case that all other forms of energy are perfectly “predictable and non-variable.”
I won’t say much about the second point, but it is obviously true. You can’t rely on being able to do whatever you want whenever you want it with whatever technology you want if we live in a world where doing these three things is causing us to lumber steadily towards self-inflicted Armageddon. Technology is not going to fix everything. We will have to make some adjustments. Please expect that and start growing accustomed to the idea now.
There is another form of variability that I want to mention: Catastrophic failure. If you build a whole bunch of wind farms across the Dakotas and Minnesota and spend the same amount on a small nuke plant somewhere in that region, catastrophic failure will have different patterns. Really bad storms, a rare earthquake, or terrorism (Canadians sneaking over the border and blowing up our stuff, presumably) will not take out all, or even most, of the wind farms, but a total “melt down” figuratively or literally, of the nuke plant will put the long term kibosh on that method of making electricity.
It is very difficult or even impossible to figure in the likelihood of catastrophic failure of any of these systems, but we can compare the form of such failure, and the worst case scenario for hundreds of wind generators distributed over three states is very different than the worst case scenario for a single nuclear power plant.
A few facts that might help frame this discussion in proper scale:
The annual generation of power at the aforementioned nuclear power plant is said to be 4,192 GWh. The plant is rated at 610 MW. That is the smaller of two plants in Minnesota, the other with an annual generation of 8,914 GWh (two 548 MW reactors).
A wind turbine may have a capacity anywhere from about 1.5 MW to over 7 MW (the latter are very rare) with the largest in design but not yet built closer to 10. Realistically, it would take about 600 to 1000 wind generators to equal this nuclear power plant. In Minnesota, the total wind energy capacity is about 2196 MW with about 10% more being constructed. This translates into 657 GWh annually, compared to 13,106 GWh annually for nuclear. The current plan in Minnesota is to more than triple wind capacity by 2021.
All the above numbers are based on capacities and estimates that may not fully add up. Another way of making the comparison is to look at recent estimates of the total percentage of energy generated by various sources statewide. At present, about 57% of our energy is from coal, 23% from nuclear, 9.4% from wind, 4.8% from natural gas and the remaining few percent from other sources. That nearly a fourth of our energy is produced by three nuclear reactors at two plants is both impressive (that’s a lot of electricity!) and somewhat concerning (that’s a lot of pressure to keep the plants working, and a big problem if one breaks).
Sources: Minnesota Energy Facts, and Wikipedia.