Gray days to deal with.
Mr. X thinks my vision of a future without nuclear power is “too hard” (“Needed: The Hard Path“). I was all set to write a post arguing about it, but something that’s not too uncommon here has given me pause—a dark and cloudy day. This is because a big part of the entire argument of whether we need nuclear power hinges, for most people, on whether or not we can make enough power from renewable sources. And THAT entire argument hinges on the question of intermittency, which is what the cloudy day reminded me of. Solar arrays can make plenty of power on a sunny day, and wind turbines can make plenty of power on a windy day, but what about all those other times? If we depended entirely on wind and solar and hydroelectric, what would we do on short winter days when the entire East coast might be having a cloudy and windless day? Or worse, a week of such days? If the energy constraints in such a system were dramatic, or if such a system was too difficult to build, it might result in that path that would be “too hard”.
So, Mr. X had a variety of points, but his main ones, including whether or not I was being consistent in my thinking, hinge around this “too hard” piece. In general, there are two broad lines of thinking here-
Line-of-thinking #1—We will need nuclear power as we move toward carbon-free sources, because wind and solar and other renewable sources are intermittent, and we will need nuclear power for baseload power. Or, related, we will need nuclear power as a transitional power source, until we build out enough wind and solar and/or develop grid-scale storage capacity.
Line-of-thinking #2—We can indeed switch over to renewable power, and the intermittency problems can be solved, and the money we would have had to spend developing safer “Gen IV” nuclear power would have been better spent on developing the truly safe and sustainable renewable system that we will need for the long term.
So, who is right? Could we make the system work with just renewable power? After some contemplation, I’ve decided that we probably can, though I admit that it will be difficult, as it will involve some fundamental changes. Some factors that make me lean in this direction—
— I think we need to undergo a paradigm shift with regard to how people expect their electricity to be delivered; the new systems will not just mimic the old. Customers today expect electricity to be generated by the utility and made continually available, in any amount, at a set rate. The system of the future might function dramatically differently from this, with the utility companies buying power from thousands or tens of thousands of producers, aggregating that power, and then making it available at a continually varying spot price. Consumers will be able to monitor this price via smart meters, and will be able to use this information to shift their demand. And, they will indeed shift their demand, because prices might vary dramatically. (And, because the generation is so dispersed, it will help moderate demands on transmission infrastructure.) This change alone would go a long way toward solving the intermittency problem—we might someday see tremendous electricity consumption during sunny hours, as people choose that time when power is plentiful (and cheap) to charge their EV’s, heat or cool their homes, run their water heaters, run their air conditioners, or, factories choose that time to conduct energy-intensive operations.
— Wind and solar complement each other really well. Germany is a good example of this—the country has 32 gw of installed solar, and about 30 gw of wind. Their solar peaks in spring and summer months, when daily solar production is about eight times higher than in December and January. But wind production is nearly the exact opposite, and the seasonal fluctuations largely balance out. (For a visual of this, see pages 13,14, and 16 of this presentation. It takes half a minute or so to load this page, but worth the wait.) Other factors also help, such as the fact that daily demand peaks in most systems during midday hours, and seasonally during the summer, exactly when solar production peaks.
Kaprun hydroelectric dam, Salzburg, Austria.
— Hydroelectric power could be held back during the day, when solar power is at its maximum, and used during nighttime hours. In many locations it can even be held back seasonally, if required. Pumped-storage systems are used in similar ways; filled when power is cheap, then used for generation when power is expensive. Other forms of utility-scale storage are being developed at a rapid rate, from compressed air storage in abandoned mines, to grid-scale liquid-metal batteries, to ideas about lifting whole mountains (TEDx Talk here), or putting together used EV battery packs in stationary locations for grid-scale battery storage. In all storage situations, the higher the difference between low and high electricity rates, the more profitable the storage—another prime situation where market-forces will help to solve a problem.
— Roofs everywhere need solar panels, even if they don’t have optimum orientations. Panels facing east and west on rooftops (and not just south) spread solar production more evenly across the course of the day (…though in the Southern Hemisphere they put solar on the northern sides of their roofs).
— The larger the geographic area that is tied together by a smart grid, the easier it is to balance power and loads. Over large areas, solar insolation averages out, as does wind production. DC transmission lines are capable of delivering power for well over 1,000 miles, and such transmission corridors could link the production from the windiest areas in the Midwest and offshore to urban centers where it would be needed, and from the sunniest parts of the country to the less-sunny (see post “This is Interesting…“). Continue reading