Chemical Energy Storage - Page 1
Forum section: electronics / general

author: msuffidy
author_rank: Frequent Contributor
timestamp: December 27, 2022, 03:24:44 am
content: I was wondering, like with regards to temporary energy storage that batteries have the problem of dying after a while. There is the solution of pumping a lot of water up a dam and then using turbines to output the gravity storage, later. So I was thinking. Maybe there is some chemical reaction that requires a lot of energy that can be reversed? So in that way it would not be an electrical battery, but would require steam driven power generation, as it outputs heat. The unit may be a lot smaller than the dam strategy.

author: IanB
author_rank: Super Contributor
timestamp: December 27, 2022, 03:40:07 am
content: Since it is burning fuel that makes heat, the chemical reaction that needs to be reversed is to "unburn" stuff. This is rather difficult to do, as the only practical ways to unburn things are to use intense heat or to use electricity. Electricity is the most efficient and controllable way of doing it, for example by splitting water by electrolysis into hydrogen and oxygen. Once you have hydrogen you can burn it to get the energy back, or you can feed it into a fuel cell to make electricity directly.Overall, electrolysis and fuel cells is the direction most people are looking at.There are possibilities using heat instead of electricity, but they have more technical challenges, especially because of the high temperatures required.

author: msuffidy
author_rank: Frequent Contributor
timestamp: December 27, 2022, 04:10:11 am
content: Oh actually yes hydrolysis and hydrogen/oxygen fuel is a really good example of something that could do that.

author: Someone
author_rank: Super Contributor
timestamp: December 27, 2022, 04:27:30 am
content: There has been plenty of work chasing that sort of idea, one example I know of:https://en.wikipedia.org/wiki/Ammonia#Fuelor the more general:https://en.wikipedia.org/wiki/Power-to-gas

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 27, 2022, 04:30:49 am
content: Nature does that pretty well by degrading organic stuff. The inconvenience is that it's rather slow, and we now tend to outrun it.

author: Swainster
author_rank: Frequent Contributor
timestamp: December 27, 2022, 05:29:19 am
content: Somewhat related, or at least it addresses the overall issue that you are referring to, without using heat as an intermediary, is the vanadium flow battery. I'm not sure whether this technology has a future, but it's worth a quick google for people interested in this subject.

author: PaulAm
author_rank: Frequent Contributor
timestamp: December 27, 2022, 02:49:45 pm
content: Flow batteries are getting quite a bit of interest. There are MWh batteries being deployed for utility use. And you're starting to see some show up for residential use. It's not quite bleeding edge, but not mainstream commercial yet.Vanadium seems to be the most common chemistry right now, but other chemistries are being explored including iron/salt. There are some advantages: generally the solutions are non (or not very) toxic, increasing capacity just means adding more tanks and they don't blow up.

author: Marco
author_rank: Super Contributor
timestamp: December 27, 2022, 05:36:01 pm
content: Batteries are chemical storage. The problem is that the most abundant materials suited for batteries (Aluminium, Iron and Zinc) tend to have unfavourable reversibility. Vanadium is nice and all, but a bit too rare for TWh scale. MIT says they have a good Aluminium Sulphur chemistry, if that could be turned into a flow battery it might be able to scale to TWh scale.PWh scale seems pretty much the domain of subterranean hydrogen storage, with its poor round trip efficiency.