What’s it going to take to substantially ramp up the amount of renewables in the electricity system? There are many nerdy discussions of that question on the interwebs, but lemme try to talk about it in reasonably non-nerdy language.
There’s a certain amount of demand for electricity that is steady and reliable. Above that, there are fluctuating “peaks” of demand each day, usually evening, when everyone gets home and starts watching TV and running the dishwasher, or in hot areas, the afternoon. For that steady core of demand, we have “baseload” power plants — in the majority of cases, large coal or nuclear plants. Once they’re built they’re pretty cheap to operate and you can run them around the clock. In nerd speak, they have a high “capacity factor.” However, they’re not well suited to ramping up and down in response to short-term fluctuations. (It takes days to turn a nuke plant off and back on.) To supply power during the fluctuating peaks, we have, appropriately enough, “peaker” plants, which can be turned on and off quickly. (Nerd speak: they’re “dispatch able.”) Generally speaking, these are natural-gas plants, which are smaller and easier to cycle, though the power is somewhat more expensive.
So you’ve got your baseload plants and your peaker plants. The fundamental problem with renewables, according to conventional wisdom, is that they are neither. They are variable and intermittent, with low capacity factors, so they can’t satisfy baseload demand. But the wind and sun are not dispatch able, so they can’t reliably satisfy peak demand either. They are an unholy mutt, a square peg for a system with two round holes.
In the U.S., already so resistant to change, the reaction has been to say, “Bummer, renewables can’t do much, woulda been nice.” When I was in Germany recently, though, the reaction among folks I talked to was, “Yes, that is a problem. We are going to solve it!” They don’t see it as the reason they can’t integrate lots of renewables. They see it as what has to be done to integrate lots of renewables. The dispute is between the Merkel government, which wants 80 percent renewables by 2050, and the Green Party, which wants 100 percent by 2030.
So, how would one go about solving the problem?