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Finnish City Inaugurates 1 MW/100 MWh Sand Battery

cleantechnica.com

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Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#151

Post by JeremyNT »

idiotsecant wrote: post #135
vjk800 wrote: post #106

Earlier quoted context omitted.

> Given the supposed 50+ year lifespan of such a battery Surely the lifespan is almost forever. It's just a tank full of sand and some heating pipes. Maybe the pipes and/or control electronics needs to be replaced occasionally, but nothing should happen to the sand inside - like ever.

'just' the piping, pumps, control systems, electrical system, valves, instruments... The sand is the least complex part. Industrial facilities like this take a lot to keep running.

I think the parent is suggesting that these things could be maintained in a cost effective way indefinitely. It's not like you hit year 50 and throw it away because of some inherent quality of the tech (as with nuclear plants or lithium batteries which fundamentally degrade in ways that are cost prohibitive to "fix").

The thing is, I'm unsure whether this holds true. Could you actually replace pipes inside a huge sand battery without bringing the entire thing offline? And at some point are you basically rebuilding it?

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#152

Post by grues-dinner »

kragen wrote: post #94
lupusreal wrote: post #84

Earlier quoted context omitted.

As I understand it, you need to limit the current flow to ground to not create a fault that burns out the whole setup. The most practical way to do that is with a bank of resistors. At that point, the resistors are doing the work and you're just using the ground as a return path, which isn't necessary.

To clarify, the current flow never goes to ground; it goes back to where it started, which is why we call it a "circuit". When you do it without routing it through a load like a bank of resistors, it's called a "short circuit". Electromechanical generators will generally tend to catch on fire if you short-circuit them. Solar panels have no problem with being short circuited; the amount of heat they produce in that st…

> Solar panels have no problem with being short circuited; the amount of heat they produce in that state is the same as any other black object in sunlight.

Internet akchually: a small amount of the heat will be dropped in the wiring that forms the short circuit rather than in the internal resistance. So the panel will be slightly cooler than you'd expect for an object of that colour even in short circuit. They're the same temperature in open circuit, though. When operating normally, they can be quite a lot cooler and in fact you can detect non-functional panels by looking for hot ones with thermal cameras.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#153

Post by bryanlarsen »

kragen wrote: post #150
bryanlarsen wrote: post #140

Earlier quoted context omitted.

Seems reasonable. I'll have to dig up my source to double check. Maybe they just didn't have Iceland data in their set? It's certainly a surprising result to see other non-sunny places like the UK, Germany, Norway & Sweden have solar as their cheapest energy source.

It's hard to get really solid estimates for solar costs because they've been dropping so precipitously, and because they depend on so many ancillary factors: wiring, inspections, permitting, power electronics, storage, and so on. Getting solid estimates for solar return on investment is even harder, because it depends on the future price of energy.

Yes, it's certainly possible that Iceland is better for solar than Finland not because of its sunlight, but because of those myriad extra factors.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#154

Post by credit_guy »

It's not clear to me why you would hold 100 hours of energy, assuming you discharge at maximum power. If you want to store energy from summer to winter, then 4 days of energy is nothing. Even if your average discharge is only 30% of the maximum power, you still get only 2 weeks of energy. And if the use case is day to night, then 8 hours of storage is enough. Maybe the idea is that the houses in Finland are so well insulated that you need heating only in cases of extreme cold, and only during the night, 100 hours will do the job?

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#155

Post by kragen »

grues-dinner wrote: post #152
kragen wrote: post #94

Earlier quoted context omitted.

To clarify, the current flow never goes to ground; it goes back to where it started, which is why we call it a "circuit". When you do it without routing it through a load like a bank of resistors, it's called a "short circuit". Electromechanical generators will generally tend to catch on fire if you short-circuit them. Solar panels have no problem with being short circuited; the amount of heat they produce in that st…

> Solar panels have no problem with being short circuited; the amount of heat they produce in that state is the same as any other black object in sunlight. Internet akchually: a small amount of the heat will be dropped in the wiring that forms the short circuit rather than in the internal resistance. So the panel will be slightly cooler than you'd expect for an object of that colour even in short circuit. They're the…

Yes, agreed, especially if you're "short-circuiting" them with MOSFETs or TRIACs or something instead of relays.

I did know that normally-operating panels were significantly cooler (23% efficiency means 23% less heat than a regular black body) but I had no idea that people used this feature to detect broken panels with thermal cameras. I'd only seen people forward-biasing the panels from an external source to stimulate NIR light emission and using NIR cameras.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#156

Post by etrautmann »

credit_guy wrote: post #154

It's not clear to me why you would hold 100 hours of energy, assuming you discharge at maximum power. If you want to store energy from summer to winter, then 4 days of energy is nothing. Even if your average discharge is only 30% of the maximum power, you still get only 2 weeks of energy. And if the use case is day to night, then 8 hours of storage is enough. Maybe the idea is that the houses in Finland are so well i…

4 days is often cited as a useful target for buffering power to backstop intermittent generation from renewable sources. You're never going to store a full winter's worth of power, and might want to be able to ride out a few days of weather.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#157

Post by bslaq »

conception wrote: post #129
echelon_musk wrote: post #120

Earlier quoted context omitted.

What does MAGA have to do with Finland?

Authoritarian populism support is rising globally.

Posting a comment doubting the ROI of a public investment is not “authoritarian populism”. If anything, democracy needs more of it.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#158

Post by dguest »

happosai wrote: post #144
dguest wrote: post #119

Earlier quoted context omitted.

Yeah I was wrong and completely misunderstood the data. I'd edit the post if I could but the timeout for that happened while I was editing. Not sure what confirmation bias I might have: I figured the Fins did their math correctly and was confused about why they were using electric heat. Anyway, to explain my mistake, the data did not look "insane" to me, it's about right for most countries, and even if it had been co…

Cheers! For the record 25% of electricity from oil is "insane" for any place that isn't a small island or failing 3rd world country.

Yeah thanks for pointing this out: I'd been confusing energy consumption with electricity generation for a while. Turns out that even countries that I thought were using oil for electricity (e.g. the US) were just using it for transportation / petrochemical.

I guess oil is too valuable to just burn.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#159

Post by yencabulator »

rsynnott wrote: post #133
csomar wrote: post #90

Earlier quoted context omitted.

The battery (am assuming it's just sand and metal) should be very cheap compared to Lithium especially in the places where you generated solar energy (they are hot and have a lot of sand). The problem is: is it profitable to even store energy there? There is no mention beyond "In operation, the sand battery has demonstrated a round trip efficiency of 90 percent.". That doesn't mean much if you do not compare it to Li…

If your house is consuming 100MWh in heating on any reasonable timescale, you, ah, have problems :)

But at least the problems will be short lived! Should reach self-ignition pretty quickly with that, even in the middle of Finnish winter.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#160

Post by Rebelgecko »

bslaq wrote: post #157
conception wrote: post #129

Earlier quoted context omitted.

Authoritarian populism support is rising globally.

Posting a comment doubting the ROI of a public investment is not “authoritarian populism”. If anything, democracy needs more of it.

The problem is when it's based on bullshit, like the secretary of energy's recent claims that completely covering the earth in solar panels wouldn't be enough energy for our needs. Like his hypothetical Dyson sphere of solar panels, a lie on Twitter can make it around the world before the truth can catch up.
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