what’s the source for the $25/kWh claim? that’s about 100x more than I was expecting.

discharged via heat exchangers to warm water for the local district heating network.

It needs certain infrastructure to work.

You could also use it to generate electricity. That's 20-40% efficient. With negative prices in summer these days that would still be interesting.

Sounds like interesting tech. But as another poster noted, to be useful it needs to be able to deliver the heat to homes, which requires a steam pipe system. Not necessarily a dealbreaker, but definitely a big up front cost that communities would need to consider.

Also, it makes sense that the battery basically just consumes electricity that would otherwise go to waste. But I think it could be an even better system if the sand were heated more directly by the sun for additional heat storage during winter.

It's interesting piece of technology, but it's not 'radical'. The company behind the storage has done their homework and they seem to be well engineered, but the "technology" itself is pretty much as old as bonfires, people have used hot rocks to heat up tents for 'a while'.

But sand has pretty good thermal properties and size of these new iterations of old tech makes them pretty decent solution for energy storage with renewables. I've been following various 'sand battery' products for our own house, but the main problem with all of them tends to be the size required. In practise for our own house we'd need a sand battery roughly the size of 6m storage container (with heat pumps and all the other hardware) and that'd be so expensive that the investment wouldn't pay itself back in my lifetime.

You need district heating for this to work. Not every place has that, so it's costly to install in places. You could use it to generate electricity, but then there are losses in the conversion.

versant-owned website. boo

That's a really great application. I wonder if a thermal battery could be used for both heating and cooling.

I personally think these types of non-conventional batteries are going to be the future of storing energy for use at offset peak usage times.

It would be great if every city could construct multi thousand megawatts of grid scale battery capacity but that probably isn't feasible with traditional chemistry batteries. But, in some areas the same effect could be accomplished with something like "potential energy batteries", for example, using massive solar arrays to pump water into an elevated reservoir during the day at peak solar generation, then releasing that water to drive turbines and generate on-demand electricity at other times.

Drake Landing Alberta

Worked well, but of course they shut it down.

I thought it was like pumped hydro but using sand! Now I'm disappointed. Still cool though, but storing heat is not a long-term solution, is it?

Pound sand, fossil fuels

Enter the sandman!

For more on strange batteries, Half As Interesting did a really cool video on different ways we do long-term energy storage.

That's so cool! It even sounds cool: sand battery.

As long as you can expect some periods of very cheap energy before its cold so you can warm it up again, seems like a decent idea actually.

How do they heat it, ideally would be using heat pumps.

I honestly thought it would be bigger. Having said that, we (as in the municipality i work for) currently have 40-60 MWh sand batteries in production. The first, small and hot, one is currently charging to go into production when it gets colder. The bigger and colder battery is slated to start charging the next season.

“And you can store it for long periods, not just two hours or four hours like lithium-ion batteries, but potentially for days and maybe even weeks.”

I'm guessing here, but "for days and maybe even weeks" must be because the battery is above ground? With good insulation seasonal storage is very much in the cards.

A day care in another Swedish municipality use about 1/5 of the "normal" energy for heating thanks to a sand battery. As in 15-18 kwh/m2/year as opposed to 70 kwh/m2/year as is the current upper limit for new buildings in Sweden.

Whoever has been paying attention to renewables knows that much better energy storage would help to solve intermittency. Personally, I've been fascinated with all the R&D being done in this field.

Why not sodium?

I've heard about so many grid storage solutions, from iron to sand apparently, but why not sodium?