What's the round trip efficiency of something like this, and what's the rate of loss to the environment? There's been a couple of these posted in the last few days and I have no feel for these numbers.
Data from Drake's Landing in Aberta has a COP of 30 (30kw of heat per kw of electricity)? The heat stored is waste heat - otherwise lost to the atmosphere, so storing it until use is should be compared to typical heat pump COP of 2-4.
The concept seems to be similar to the "Gridscale Storage"[0] system sold by Stiesdal technologies[0], which claims a round-trip efficiency of 55-60%.
The important insight here is that per Carnot's law[1], the higher the storage temperature the higher the theoretical max efficiency for thermal storage. Stiesdal had an initial concept that stored at even higher temperatures (1000C) and used a standard power plant steam turbine for converting back to electricity. But these turn-key solutions are probably more realistic.
If you are interested in realistic renewable energy, do browse the Stiesdal pages: Henrik Stiesdal [2] was pretty much the inventor of the modern wind turbine (sold the upwind 3-blade design to Vestas, CTO at Siemens Wind Power): He seems to have a superb intuition for industrializing heavy machinery. I am keenly following his advances into electrolysis and floating offshore wind power.
This was the question I came to pose... This is such an exciting field but when the CORE most important variable is missing, I tend to assume the worst - in this case being that the value is atrociously low.
The RTE of turning electricity into heat (or hot water into hot sand into hot water) is pretty good, most of your problem will be environmental losses between the heating station and the end-users.
It's not going to be as good as a heat pump, but they don't work very well in very cold climates, and storing electricity (or energy that you turn back into electricity) is expensive/lossy/difficult.
jpollock|3 years ago
https://www.dlsc.ca/
https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community
TheSpiceIsLife|3 years ago
It's electricity powered thermal storage for municipal heating.
Which, in my opinion, is a smart idea. Why bother converting the heat back to electric to end up being used to generate heat in homes.
You could use this as a heat sink at the home attached to a high efficiency heat pump for 6:1 thermal efficiency.
We could do with municipal heating here in Tasmania
japanuspus|3 years ago
The important insight here is that per Carnot's law[1], the higher the storage temperature the higher the theoretical max efficiency for thermal storage. Stiesdal had an initial concept that stored at even higher temperatures (1000C) and used a standard power plant steam turbine for converting back to electricity. But these turn-key solutions are probably more realistic.
If you are interested in realistic renewable energy, do browse the Stiesdal pages: Henrik Stiesdal [2] was pretty much the inventor of the modern wind turbine (sold the upwind 3-blade design to Vestas, CTO at Siemens Wind Power): He seems to have a superb intuition for industrializing heavy machinery. I am keenly following his advances into electrolysis and floating offshore wind power.
[0]: https://www.stiesdal.com/storage/the-gridscale-technology-ex... [1]: https://en.wikipedia.org/wiki/Carnot_cycle#Carnot's_theorem [2]: https://en.wikipedia.org/wiki/Henrik_Stiesdal
loufe|3 years ago
vkou|3 years ago
It's not going to be as good as a heat pump, but they don't work very well in very cold climates, and storing electricity (or energy that you turn back into electricity) is expensive/lossy/difficult.
timbit42|3 years ago
https://www.dailymail.co.uk/sciencetech/article-10982885/Wor...