Years ago, I wrote a site full of daft ideas about energy production. The site was mostly an experiment with Wiki technology; I guess that time has passed, but I was also fascinated but different ways that we could generate and use energy. This post is a resurrection of that idea.
I have been thinking recently about energy storage. There has a lot of interest in long term, seasonal storage of renewable energy. The problem here is clear; the two highest volume forms of renewable energy are solar and wind; both are very dependable but intermittent both daily and seasonally. To some extent they complement each other – solar works during the day, wind in the evening, solar during summer, wind during winter. But, it is not enough; we need to store it also.
Batteries are great. Lithium technologies work well and can largely resolve the daily variation problem; they are being deployed both in homes and at grid scale to solve this problem; and, as small-scale batteries are all internet connected, small-scale can be virtually large scale also. So that is the daily variation solved.
But lithium is too expensive for longer time durations. There are a variety of solutions here; vanadium flowA batteries are probably most advanced on the grid connected front, but iron-air or zinc-air are making great steps toward large-scale commercialisation; on top of that, we have compressed gas/air in varying stages of development. So, that’s weekly variation being worked on.
That leaves us with seasonal variation. There are various discussions about this, including thermal storage, but an obvious one is hydrogen. We already have lots of technology for this, as it is similar to methane. But, there is a problem. The roundtrip efficiency is not great; we lose a lot to heat.
Interestingly, we are now seeing home hydrogen becoming possible. This system is meant for residential storage, essentially as a battery. But, of course, it could also be used as part of a virtual large-scale hydrolyser. Taking energy from the grid, turning it into hydrogen and then feeding it back to the gas network.
What is the point of this? Well, it avoids the problem of waste in the transformation. If we have daily and weekly storage working problem from batteries, the cost variation of electricity will happen on a seasonal rather than daily basis. So, we can hydrolyse water when we want in winter; if we can do it at home as well, we can simply dump the heat produced by the hydrogen electrolysis in the heating system of the house; no longer is the heat wasted, it now warms the house instead. Although the hydrolysis would be intermittent, because we’d only do it when the heating is on, over a season you could depend on the quantities produced.
Of course, all this might be too complex for a home, but large buildings like hospitals could use the technology instead, or district heating systems; they wouldn’t even need to use the gas mains; we could send a lorry when their storage is full.
And that is my first daft energy post for many years!