Just five posts in and I’ve already been seduced by my inner essayist. I don’t really mind, because Dave’s Made-Up Law of Pressure says that if you create an opening, what comes out first is what really wanted to come out. I didn’t know writing a blog would be this much fun. At the same time, I don’t want to keep eddying around in interesting side topics, without quite getting to the specific reason I started a blog.
That reason was to discuss possible technology ideas for addressing climate change. Some that I came up with, and some not, but in any case, ideas:
- that just might work,
- that just might have a noticeable impact on our climate disaster in progress, and
- that some of us just might be able to get together and build.
There are three ideas on my list at the moment. (There are also some ideas on the scrap heap that I was excited about at one time, but I finally concluded that they wouldn’t work, they wouldn’t have much impact, or our society, in its current form, could never pull them off.)
My three contenders right now are:
Making our houses, apartments, and workplaces so energy-efficient that “you can heat the place with a match.” This isn’t my idea; they’ve been doing it for decades in Germany and other places1. No technological breakthroughs are needed. Done correctly, it’s 100% upside and plenty of it. The only real question is why we aren’t doing it, and the short answer is that we expect individual property owners to take one for the team, and spend more of their own money than they’ll ever recoup, because it’s good for everybody else. We need to reject that magical thinking, and start using societal resources to achieve societal benefits.
#2: Household-scale thermal energy storage using PV + heat pump + thermal reservoir.
This concept may be out there, but I haven’t run across it. In sketch form:
a) you have a heat pump to heat and cool your house.
b) you have a good-sized array of solar panels on your roof. This means you’ve got your own cheap supply of electricity, part of the time.
c) you have a cistern in your basement or buried in your yard, which is well-insulated and holds a lot of water.
d) the heat pump is rigged to be able to exchange energy, not just with the living space and the outdoors, but with the cistern too.
e) on a sunny winter day, you can run your heat pump hard because you’re getting cheap solar electricity. The heat pump (in addition to heating the house) is taking energy from outdoors and moving it into the cistern, giving you a reservoir of very warm water. After the sun goes down, the heat pump (or just a circulating pump, when the water’s hot enough) moves this energy from the cistern into your living space, giving you heat almost for free—possibly right up until the sun comes back tomorrow, if the cistern’s big enough and warm enough.
f) on a sunny summer day, again, you can run your heat pump hard on cheap solar electricity during those precious midday hours when the sun is strong. The heat pump (in addition to cooling the house) is taking energy from the cistern and moving it outdoors, giving you a reservoir of very cold water. After the sun goes down, when your living space is at its hottest, the heat pump (or just a circulating pump, while the water’s cold enough) moves energy out of the living space and into the cistern, giving you air conditioning almost for free—all night if you need it, provided the cistern’s big enough and cold enough.
This is a short-term form of demand shifting—saving energy for a few hours later, when you need it more. Obviously, a bigger cistern would give you more duration, but I think the sweet spot is in the 3-to-12-hour range, like the scenario I’ve described. Many dwellings are heated by natural gas and cooled by fossil electricity, so the potential carbon reduction is considerable.
#3: Grid-scale electricity storage using encapsulated pumped hydro.
First we had hydropower (Grand Coulee Dam, for example). Electricity is generated by the force of water falling from a higher elevation to a lower one. It’s a carbon-free energy source, and because it dams a river to form an artificial lake, it has storage built in. Great stuff, except we’re out of rivers to build it on, and reluctant to devastate what rivers we have left anyway.
Then came pumped hydroelectric storage (often just called “pumped storage,” or “pumped hydro”). Dating back to 19072, this doesn’t produce energy, but it does store it for use at a more convenient time. Early examples were built around existing bodies of water, doing environmental damage similar to that caused by hydroelectric dams, though not on such a grand scale.
Later, closed-loop pumped hydroelectric storage was invented. This uses the same water over and over, pumping it between two elevations to alternately store and release electricity. A key benefit of this scheme is that it doesn’t have to connect to any natural bodies of water at all, so the environmental issues are lessened. A number of new projects of this type are planned or under construction, using moderately-sized dams in combination with natural terrain to build two artificial lakes at different heights.
Finally, my proposal, which I call encapsulated pumped hydroelectric storage (or “encapsulated pumped storage” for short). The motivation is that (a) the arid Southwestern U.S. has an abundance of great sites for closed-loop pumped hydro, on land of little competing economic value, but (b) open reservoirs in that climate would have unacceptable water losses due to evaporation. So, instead of reservoirs, store the water in a number of very large, individual, above-ground, flexible tanks (or “bags”).
This has many advantages besides preventing evaporation. The cost should be significantly less than the massive earth-moving and damming needed to make two large reservoirs. The carbon debt due to materials and construction would also be far smaller than with concrete dams. The system could be built out incrementally over many years, instead of requiring a decade or more of sunk costs before any benefit is returned. The environmental impact could be much smaller as well. Modularity means maintenance can take place without shutting down the whole system. And sites could be used that aren’t suitable for reservoir-building (particularly at the higher of the two elevations).
Those are three things I would like to try. I’ll look at each of them in much more detail in future posts. By “try,” I mean a series of actions: first, to build them, at mini-scale if necessary. I also want to “try” them in the judicial sense: examine and analyze them from every angle, look for flaws, run software simulations, compute the costs and the benefits as accurately as possible, and see if they really make sense. Finally, if some or all of these ideas still look good after that, trying them would mean writing proposals, seeking funding, and putting together resources and people to build them at scale, and find out if they can really make a difference.
And whether these ideas make the cut or not, I’ll be keeping an eye out for others. The challenge is big, and we need a network of many partial solutions addressing different areas, at every scale from individual to global.