In an interview published in The Atlantic, billionaire Microsoft founder Bill Gates had two very astute observations about wind and solar energy:

On the limits of wind power and solar photovoltaic cells:

Wind has grown super-fast, on a very subsidized basis. Solar, off a smaller base, has been growing even faster—again on a highly subsidized basis. But it’s absolutely fair to say that even the modest R&D that’s been done, and the various deployment incentives that are there, have worked well. Now, unfortunately, solar photovoltaic is still not economical, but the biggest problem of all is this intermittency. That is, we need energy 24 hours a day. So, putting aside hydro—which unfortunately can’t grow much—the primary new zero-CO2 sources are intermittent. Now, nuclear is a non-CO2 source, but it’s had its own problems in terms of costs, big safety problems, making sure you can deal with the waste, making sure the plutonium isn’t used to make weapons. So my view is that the biggest problem for the two lead candidates is that storage looks to be so difficult. It’s kind of ironic: Germany, by installing so much rooftop solar, has it that both their coal plants and their rooftop solar are available in the summer, and the price of power during the day actually goes negative—they pay people to take it. Then at night the only source is the coal, and because the energy companies have to recover their capital costs, they either raise the price because they’re not getting any return for the day, or they slowly go bankrupt. There are many people working on storage—batteries are a form of storage, and there’s a few others, like compressed air, hot metals. But it’s not at all clear that we will get grid-scale economic storage. We’re more than a factor of 10 away from the economics to get that.

On the self-defeating claims of some clean-energy enthusiasts:

They have this statement that the cost of solar photovoltaic is the same as hydrocarbon’s. And that’s one of those misleadingly meaningless statements. What they mean is that at noon in Arizona, the cost of that kilowatt-hour is the same as a hydrocarbon kilowatt-hour. But it doesn’t come at night, it doesn’t come after the sun hasn’t shone, so the fact that in that one moment you reach parity, so what? The reading public, when they see things like that, they underestimate how hard this thing is. So false solutions like divestment or “Oh, it’s easy to do” hurt our ability to fix the problems. Distinguishing a real solution from a false solution is actually very complicated.

Right. Which is why the demand to rush the replacement of fossil fuels with wind and solar is a death knell to the world’s poor.