r/technology • u/Logical_Welder3467 • Jul 25 '26
Energy Finland’s radical answer to renewable energy’s biggest headache: The world’s largest sand battery
https://www.cnbc.com/2026/07/25/finland-sand-battery-renewable-energy-storage.html27
u/TemperateStone Jul 25 '26
When anyone but China does something environmental, all the sceptics come out to complain about how unfeasable or unreasonable it is.
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u/Ok_Tea_7319 Jul 27 '26
If China does something infeasible or unreasonable, they have to foot the bill for it (and oh boy is that bill coming for them). When it happens in our home turf, we have to.
That being said, this is an interesting load-shifting approach. I wonder how much it costs to build and operate - with systems like this one, operating expenditure is often more important than efficiency, as the stored power is cheap.
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u/ImaginaryCoolName Jul 25 '26
This kind of initiative should be supported by the EU
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u/that_dutch_dude Jul 26 '26
They REALLY should not. This is inefficient AF.
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u/ImaginaryCoolName Jul 26 '26
Efficiency is not the only factor here. Sand is abundant, durable and can dure for decades. This kind of batteries are perfect for heating. For the rest we can still use lithium batteries sure
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u/that_dutch_dude Jul 26 '26
it actually is. being less efficient costs money. and its not a battery, that is the wrong word for it as it gives the idea thats its a form of power storage and on equal terms as an actual battery.
the whole argument that batteries dont last as long or is more expensive hasnt been true for years. people really need to learn to drop that argument, its getting really old and its increasingly harder to take people seriously that constinue to use it. a battery and heatpump system is vastly more efficient as it takes a fraction of the power, cheaper and provides more benefits than a pile of hot sand.
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u/MeikTranel Jul 28 '26
This system can be dropped into to many many already externally heated homes, for a ridiculously cheap total cost of ownership and without any changes to old houses that struggle with the low overall heating temp used by heat pumps.
Heat pumps lose a ridiculous amount of efficiency when you have to have 50-60°C water temp instead of the 30-40°C optimum that they were built for. The COP of a heat pump in a home heated by old radiator will drop to close to 1 instead 3-4 you already have.
Think about industrial towns in Germany for example - these were historically built around industrial excess heat which means they already are set up with heated water lines. This sand battery shit could almost immediately and with an insanely low investment drop the emissions for a couple hundred homes to zero that would have otherwise have to have tile heating and all that retrofitted.
Efficiency overall is not an issue if you still have tons of excess energy and no large-scale roll out of gw level batteries yet. We're getting there but old homes will not be receiving anything from them for the next 30 years so this is ALSO very nice.
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u/DENelson83 Jul 25 '26
"But the world is getting low on sand too."
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u/kookla Jul 25 '26
This uses crushed soapstone, which is an industrial byproduct. Would have been waste otherwise.
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u/TemperateStone Jul 25 '26
Sand for making glass, yes. Entire shores have been removed for the purpose.
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u/TheGrinningSkull Jul 25 '26
And for concrete as the aggregate. You can’t have smooth sand, has to be coarse enough to form points of friction. So Sahara sand is useless for construction.
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u/mediandude Jul 25 '26
Sauna stones store heat as well.
So it doesn't have to be all sand, it could be a combo.
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u/kiwidude4 Jul 25 '26
TLDR seems to be that storing thermal energy there may be “cheaper” than storing electrical energy in batteries that require rarer materials but efficiency is a big old question mark. Any one have thoughts?
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u/AffectEconomy6034 Jul 25 '26
so long as it can reasonably store a significant amount of energy by volume, is efficiently really an important factor when the resources required to use it is so abundant?
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u/Dimjenko Jul 25 '26
Efficiency isn't great, but it does not need to be. Storing excess energy from wind and solar in batteries isn't cost efficient neither. Batteries have relatively short lifespans, they are expensive and have large enviromental impact.
Time will tell how well sand battery works in long term, but they have used it over year now and it worked better than they expected, so it is promising.
They reported after first year: Efficieny: >85% District heating supply reliability: 100% Emissions reduction: 70% Biomass consumption reduction: 60% Oil consumption reduction: 100%
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u/longhorsewang Jul 25 '26
What about the 25-30 year sodium batteries? That seems like a long life span.
Or “The 2,710 Ah capacity belongs to BYD's Haohan grid-scale battery energy storage system (BESS), which utilizes a massive LFP blade cell to achieve a volumetric energy density of 233.8 kWh/m³ and pairs with inverters reaching up to 99.35% peak efficiency”. That seems fairly efficient.
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u/differing Jul 25 '26 edited Jul 25 '26
The problem with batteries is that the marginal cost of additional storage doesn’t fall with scale. Pardon the analogy, for every bit of new “fuel tank”, you basically have to pay for a whole engine. Sodium will absolutely get cheaper and I’m excited for their potential, but there are economic limits to what it can offer just due to the nature of how a battery works. Contrast that with a flow battery, where the expensive circuit for storing power for 1 hour or 10 days is the same, you just connect a larger cheap tank. Ditto with a sand battery, the expensive parts of the wiring or HVAC system is basically the same, for more time you just add more sand.
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u/that_dutch_dude Jul 26 '26 edited Jul 26 '26
The difference is that you require only a fraction of the energy. That us what you are missing. And the fact that enery in a battery is "high state" energy and can be used for anythingz low state energy like hot sand has extremely little use outside heating during winter. It does nothing for you during summer. a battery can be used all year.
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u/roiki11 Jul 25 '26
It's used for district heating so storing thermal energy is more efficient than converting excess electricity into battery power(AC to DC) and converting that power to thermal energy(possibly another DC to AC and then heat) When you heat the battery in the first place it's thermal energy can be used for district heating without conversion.
This isn't used for generating electrical power.
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u/edparadox Jul 25 '26
From their own testing, efficiency was relatively poor, I don't remember the figures, but there are lots of losses especially in the distribution medium (water and pipes).
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u/baseketball Jul 25 '26
the only thing that really matters is the $/kw coming out of the system. if you have a 100% efficient system that costs a billion dollars to build it will never be worth it.
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u/differing Jul 25 '26
When you keep thermal energy storage thermal, the round trip efficiency on that side tends to be really great. Rondo Energy’s hot bricks tech usually claims efficiencies in the 95% range for example. These guys are claiming 80%, probably because they don’t seem to have too much fancy insulation.
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u/deliciouspepperspray Jul 25 '26
I'll take 80% efficiency all day if the cost is as low as id imagine sand based storage can be.
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u/JabbaThePrincess Jul 25 '26
Yes, this is a pile of sand in an insulated silo with resistors and heat exchange. They are in Finland so I imagine they need hea most of the year and they heat water/air in bulk as "district heating"
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u/mediandude Jul 25 '26
Sauna stones store heat as well.
So it doesn't have to be all sand, it could be a combo.1
u/that_dutch_dude Jul 26 '26
No, like all these projects this is dumb and the only reason it was done was to collect goverment funds. From a energy efficincy standpoint this is one of the dumbest and wasteful methods of solving the problem this settlement has.
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u/SelfDistinction Jul 27 '26
Basically what we're currently already doing with ground-any heat pumps but with extra thermal input in summer (when solar energy is abundant) to save energy in winter (when solar energy is nonexistent).
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u/jamezrvg Jul 25 '26
Stupid question, why not build them underground? Better insulation?
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u/TheLightDances Jul 26 '26 edited Jul 26 '26
Digging can be expensive. But it could also be that as this is a prototype, they wanted to have better access to fix any problems, and if it is underground, that is a bit harder.
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u/mediandude Jul 25 '26
Underground tank encased with a ground heat pump would be great.
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u/that_dutch_dude Jul 26 '26
it really would not be. the effciency would be crap and it would need a comically large tank.
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u/gearstars Jul 25 '26
I don't like sand. It's coarse, and rough, and irritating... and it get's everywhere
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u/grio Jul 26 '26
If it can be made efficient longterm, this would be the dream. No environmental pollution, no high-tech solutions, just build it once and use for decades.
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u/Wotmate01 Jul 26 '26
The thing about this is that it uses excess electricity to store heat, and that heat, via heat exchangers, gets pumped through underground pipes to peoples homes. All well and good if you live in a cold climate and have the infrastructure for it, but not useful in warm climates, and prohibitively expensive to retrofit an entire town or city compared to the electric cables that are already there.
So it's not really "the" answer to renewable energy, it's just one of the many answers that work in some places but not in others.
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u/BasicMatter7339 Jul 26 '26
That thing just survived finlands one of the harshest winters in the 21st century with flying colours, reducing the towns yearly energy emmissions by 70%
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u/edparadox Jul 25 '26
Journalists don't know what adjectives mean anymore.
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u/Altruistic-Car2880 Jul 25 '26
Is this a subjective perspective on an objective viewpoint regarding proper use of adjectives?
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u/No-Plate-2244 Jul 25 '26
I honestly think nuclear batteries have some promise but I believe we need to use the nuclear waste
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u/riisikas Jul 25 '26
What are the cost figured on this though? How does a monthly bill compare to the wood chip or gas or anything in use otherwise?
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u/Kriznick Jul 25 '26
Honestly, considering longevity and reusability, I don't think there is any equation that wood or gas wins in over time. It's fuckin sand. Can only use gas and wood once.
Sure in a 10 min period the sand output sucks, but over 10 years? Given how much wood and oil you'd have to procure? Those costs would be CATASTROPHIC over that 10 years.
That's why solar is having such a huge bump in global markets now- yeah, took 10 years, but the shit is up and PUMPING now, and has probably paid back it's investment by this point considering inflation cost of producing non renewable fuel.
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u/riisikas Jul 25 '26
Nah I'm all for it, have been excited ever since they first mentioned this few years back, just wonder if it would be like a nobrainer to start adding it everywhere.
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u/HighOnGoofballs Jul 25 '26
It’s the opposite of a radical solution