Innovative sand battery can heat entire town for a week

[Shawn Knight]

Forward-looking: A Finnish startup has secured $7.6 million Euro ($8.2 million) in seed funding to scale up its unique sand battery technology. The money will be used to grow the company's sales and R&D teams, and help advance the tech's capabilities. But what exactly is a sand battery, anyway?

A sand battery uses sand or sand-like material as a medium to store energy as heat. Its core purpose is to serve as a high-capacity reservoir for surplus wind and solar energy. The unit consists of an insulated silo filled with sand, and is outfitted with heat transfer pipes and tech to convert electricity to heat. When needed, heat can be extracted from the system for a variety of uses.

The system doesn't rely on exotic materials, either. The company said sand grain size isn't all that important, and they prefer to use materials that aren't typically used in the construction industry.

Polar Night Energy installed its first sand battery in Vatajankoski's district heating network in Kankaanpää, Finland, which went into service in 2022. That battery affords 100 kW of heating power and 8 MWh of capacity.

Last month, Polar Night Energy announced it had partnered with Finnish district heating company Loviisan Lämpö to build an industrial-scale sand battery in Pornainen. The unit will measure approximately 13 meters (42.7 feet) high and 15 meters (49.2 feet) wide, and will take a little over a year to construct and test.

Once operational, the bigger battery will be able to store up to 100 MWh of thermal energy and provide 1 MW of heating power. In Pornainen, that'll translate to a full week of heat supply in the winter and nearly a month's worth during the summer.

The sand inside the battery can be heated to more than 1,000 degrees Celsius and is typically limited by the heat resistance of the materials used in construction of the storage facility. Polar Night Energy said its storage system can even be built underground, ideal for regions where real estate is highly valued.

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Innovative sand battery can heat entire town for a week

 

[WhiteLeaff]

This technically shouldn't be called a battery.

 

[Vanderlinde]

This technically shouldn't be called a battery.

It's simular tech as sending a satellite up in space with a nuclear element that is constantly radiating or "heating" and used with TEC's to convert the heat into electricity.

just using heat as a form of energy (stored).

 

[Endymio]

Yes, it's an actual battery. But it's hardly new tech -- such thermal storage solutions have been tried before. The primary issue is their low efficiency -- smaller installations can easily lose half the stored energy in through conductive cooling. And then, if you want the energy in the form of electricity rather than pure heat, expect another 50% loss on that conversion as well, with an E2E efficiency of 25% or less.

A very large subterranean system can be more efficient, but even here unless you're planning on consuming most of the stored energy as heat itself, it's not economical.

 

[toooooot]

Yes, it's an actual battery. But it's hardly new tech -- such thermal storage solutions have been tried before. The primary issue is their low efficiency -- smaller installations can easily lose half the stored energy in through conductive cooling. And then, if you want the energy in the form of electricity rather than pure heat, expect another 50% loss on that conversion as well, with an E2E efficiency of 25% or less.

A very large subterranean system can be more efficient, but even here unless you're planning on consuming most of the stored energy as heat itself, it's not economical.

They must have discovered new ways or new materials that make it more viable now

 

[ScottSoapbox]

They must have discovered new ways or new materials that make it more viable now

It sounds like they are using it for the heat (at a later time) and therefore sidestepping the loss of the transfer back to electricity.

 

[VitalyT]

The word Battery implies portability. A house-size fixed installation doesn't qualify.

 

[Aranarth]

The word Battery implies portability. A house-size fixed installation doesn't qualify.

BZZZT!!! wrong!

Battery definition:
bat·ter·y
/ˈbadərē/
noun
noun: battery; plural noun: batteries; noun: the battery

1.
a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.
"battery power"
h
Similar:
cell

accumulator
power unit
2.
a fortified emplacement for heavy guns.
"anti-aircraft missile batteries"

an artillery subunit of guns, men, and vehicles.
h
Similar:
gun emplacement

artillery unit
artillery
cannonry
ordnance
heavy weapons
heavy weaponry
guns

cannons

3.
a set of units of equipment, typically when connected together.
"a battery of equipment to monitor blood pressure"
h
Similar:
array
set
bank
group
row
line
lineup
raft
collection
assortment

an extensive series, sequence, or range of things.
"children given a battery of tests"
h
Similar:
series

sequence
range
set
cycle
chain
string
progression

succession

4.
Law
the crime or tort of unconsented physical contact with another person, even where the contact is not violent but merely menacing or offensive.
"any act which puts a person in immediate and reasonable fear of battery"
h
Similar:
violence
assault
mugging
beating
striking
thumping
thrashing
bashing
grievous bodily harm
actual bodily harm
GBH
ABH
5.
Baseball
the pitcher and the catcher in a game, considered as a unit.

In this case definition 3 applies.

 

[VitalyT]

BZZZT!!! wrong!

Battery definition:
bat·ter·y
/ˈbadərē/
noun
noun: battery; plural noun: batteries; noun: the battery

1.
a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.
"battery power"
h
Similar:
cell

accumulator
power unit
2.
a fortified emplacement for heavy guns.
"anti-aircraft missile batteries"

an artillery subunit of guns, men, and vehicles.
h
Similar:
gun emplacement

artillery unit
artillery
cannonry
ordnance
heavy weapons
heavy weaponry
guns

cannons

3.
a set of units of equipment, typically when connected together.
"a battery of equipment to monitor blood pressure"
h
Similar:
array
set
bank
group
row
line
lineup
raft
collection
assortment

an extensive series, sequence, or range of things.
"children given a battery of tests"
h
Similar:
series

sequence
range
set
cycle
chain
string
progression

succession

4.
Law
the crime or tort of unconsented physical contact with another person, even where the contact is not violent but merely menacing or offensive.
"any act which puts a person in immediate and reasonable fear of battery"
h
Similar:
violence
assault
mugging
beating
striking
thumping
thrashing
bashing
grievous bodily harm
actual bodily harm
GBH
ABH
5.
Baseball
the pitcher and the catcher in a game, considered as a unit.

In this case definition 3 applies.

What they made is a stationary heat storage, which can convert heat into electricity on demand, it is not a battery.

 

[Endymio]

The word Battery implies portability. A house-size fixed installation doesn't qualify...[it] can convert heat into electricity on demand, it is not a battery.

Volta's original battery wasn't portable, and there are already lithium-ion batteries larger than an entire football field -- Tesla built one in 2017 to power an entire town. Grid-scale batteries utilizing pumped hydro are even larger. And all batteries work by converting some other form of energy into electricity on demand., usually chemical. Excepting ultracapacitors, the electricity isn't already there inside, floating around on its own.

If you wish to be truly anal about language -- like myself -- the word battery originally denoted a "battery of units" -- an assemblage of multiple electrochemical cells, each generating its own electricity independently. Volta's original unit was a "battery" of two dozen such cells piled atop each other. By this stricter definition, Tesla's football-field-sized battery qualifies as such, but the "single cell" 1.5v batteries you've been using your entire life do not.

 

[Aranarth]

What they made is a stationary heat storage, which can convert heat into electricity on demand, it is not a battery.

Definition 3 STILL applies.
however I will concede that "Bank" might be a better word to use rather than battery.

 

[maxxcool7421]

What they made is a stationary heat storage, which can convert heat into electricity on demand, it is not a battery.

the dictionary disagrees with you

 

[Reachable]

Evidently the meaning of the word "battery" has expanded to include any device that can be "charged" via the use of any form of energy and then discharged via the use of any form of energy.

 

[WhiteLeaff]

It's like referring to a large tank of water, filled via a solar-powered pump from a lower point, as a battery simply because you can convert water back into electricity... it doesn't make sense.

 

[Endymio]

It's like referring to a large tank of water, filled via a solar-powered pump from a lower point, as a battery simply because you can convert water back into electricity... it doesn't make sense.

Interestingly enough, hydro-pumped facilities are indeed referred to as "the world's largest batteries". They store energy, and release it as electricity on demand -- the modern definition of the term. Would you be more comfortable calling it a battery if your "large tank" was the size of a D-Cell flashlight battery, and produced electricity as the water inside flowed downward?

Words change meaning over time. A "deer" used to mean any animal at all, if you worked in an "office", it meant you were a member of the Church, and the terms "awesome" and "awful" used to mean the same, rather than polar opposites. Originally the term battery meant a group of units working together, such as an artillery battery. But "a battery of voltaic cells" was too cumbersome, so it became shortened to just "battery" -- even when we're only talking about one cell alone.

 

[WhiteLeaff]

Interestingly enough, hydro-pumped facilities are indeed referred to as "the world's largest batteries". They store energy, and release it as electricity on demand -- the modern definition of the term. Would you be more comfortable calling it a battery if your "large tank" was the size of a D-Cell flashlight battery, and produced electricity as the water inside flowed downward?

Words change meaning over time. A "deer" used to mean any animal at all, if you worked in an "office", it meant you were a member of the Church, and the terms "awesome" and "awful" used to mean the same, rather than polar opposites. Originally the term battery meant a group of units working together, such as an artillery battery. But "a battery of voltaic cells" was too cumbersome, so it became shortened to just "battery" -- even when we're only talking about one cell alone.

I can poetically call anything a battery, but it's not accurate to refer to sand storing heat or a dam storing water as a battery.

I'm not a fan of this juggling of words.

 

[Pantomime9270]

Galvanic Cell - Stores energy in form of Chemicals
Dam - Stores energy in form of Potential Energy of water
Capacitor - Stores energy in Electric Field
Inductor - Stores energy in Magnetic Field
Flywheel Battery - Stores energy in Rotational motion
Radioactive atoms(?) - Stores energy in form of unstable Nucleus
Sand Battery - Stores energy in form of Heat (there are other ways to store energy in the form of Heat https://en.wikipedia.org/wiki/Thermal_energy_storage)

These are all that I can come up with, will edit if find more.

 

[ferrellsl]

Sand isn't a very good storage medium for heat. Underground water tanks make for much better thermal storage and they're cheap. This whole thing sounds like an investment scheme designed to rob unwitting investors.

 

[Endymio]

Sand isn't a very good storage medium for heat. Underground water tanks make for much better thermal storage and they're cheap....

The thermal conductivity of sand is much lower than water, meaning it holds heat much longer. Also, being a solid, it loses heat via conduction, rather than convection, which is a primary point in its favor -- the heated sand cools more rapidly at the boundaries than at the superheated center.

Finally, while underground water tanks may be cheap, there's nothing cheaper than a huge pit backfilled with sand.

 

[ferrellsl]

The thermal conductivity of sand is much lower than water, meaning it holds heat much longer. Also, being a solid, it loses heat via conduction, rather than convection, which is a primary point in its favor -- the heated sand cools more rapidly at the boundaries than at the superheated center.

Finally, while underground water tanks may be cheap, there's nothing cheaper than a huge pit backfilled with sand.

Yeah, which also means that it takes an eternity to heat it up, unlike water, so a lot of energy is wasted in the transfer process. If this was such a wonderful idea people everywhere would already be using it. And they're not and they won't.

 

[Endymio]

Yeah, which also means that it takes an eternity to heat it up, unlike water, so a lot of energy is wasted in the transfer process.

Your science is confused here. Thermal conductivity only affects the rate at which heat flows on its own accord. But this sand is heated inductively via electrical current, at a rate driven by the amount of energy added to the system. And the efficiency of this leg of the transfer is exactly 100% -- like all such systems.

If this was such a wonderful idea people everywhere would already be using it. And they're not...

As already pointed out, this is -not- a wonderful idea. It makes sense economically here only because both (a) most of the energy is extracted as heat, not electricity, and (b) the inputs are "green" energy that would otherwise go to waste entirely.

My original point to you is that "tanks of water" would be an even less wonderful idea than the sand they've chosen as a medium.

 

[ferrellsl]

Your science is confused here. Thermal conductivity only affects the rate at which heat flows on its own accord. But this sand is heated inductively via electrical current, at a rate driven by the amount of energy added to the system. And the efficiency of this leg of the transfer is exactly 100% -- like all such systems.


As already pointed out, this is -not- a wonderful idea. It makes sense economically here only because both (a) most of the energy is extracted as heat, not electricity, and (b) the inputs are "green" energy that would otherwise go to waste entirely.

My original point to you is that "tanks of water" would be an even less wonderful idea than the sand they've chosen as a medium.

Where is this "here" that you speak of? Because this method makes no economic sense "anywhere"! People have been using water to store heat for centuries and it's a proven and inexpensive technology. This turd hasn't even made it off the ground yet and they're asking for investment money that investors will never see again. As for heating towns in Finland, geothermal heating is an option that is proven, inexpensive, and available. The geothermal heating plant built by QHeat for Vantaan Energia in the district of Varisto in Vantaa, Finland has already started operations. It consists of three heating wells about 800 meters deep. The sand battery is an expensive solution looking for a problem.

 

[mbk34]

Sand isn't a very good storage medium for heat. Underground water tanks make for much better thermal storage and they're cheap. This whole thing sounds like an investment scheme designed to rob unwitting investors.

Water can hold 3 times more energy than sand but only up to 100C (212F). This sand battery goes up to 1000C (1830F). That means it will make a much better battery than water. Here in the UK we had storage heaters that heat bricks using cheap electricity at night to then heat homes during the day. This sand battery is just a much more efficient and higher capacity version of the same. This sort of thing will do very well in colder areas where there is a lot of green energy and people live communally.

 

[ferrellsl]

Water can hold 3 times more energy than sand but only up to 100C (212F). This sand battery goes up to 1000C (1830F). That means it will make a much better battery than water. Here in the UK we had storage heaters that heat bricks using cheap electricity at night to then heat homes during the day. This sand battery is just a much more efficient and higher capacity version of the same. This sort of thing will do very well in colder areas where there is a lot of green energy and people live communally.

I don't care what country you're from. As you even noted, water is 3 times more efficient than sand at storing heat. BTW, the average melting point of copper cables is 1085C so how do you propose keeping the transmission cables connected to any heating elements from melting when the sand reaches your magic 1830C? And the cost to construct solar farms and windmills and connecting cables and heating elements to underground sand pits far outstrips the cost of geothermal wells. The costs to construct windmill farms and solar farms to heat such pits are more expensive by a factor of 10. You're also not factoring in the maintenance costs of windmills or solar farms. Again, if rocks and sand made sense for thermal storage and heating towns, it would already be in use the world over but it isn't for very good reasons.

 

[Endymio]

.People have been using water to store heat for centuries and it's a proven and inexpensive technology ...

People have been using heated stone and rock to store heat for even longer; it's even more inexpensive -- no water tanks required.

You don't seem to realize that different applications require different solutions. For thermal storage at lower temperatures, water is by far the most energy-dense material. But water loses heat very quickly, which isn't a big problem for, say, adding thermal mass to a building to mediate daily temperature swings. But it's an enormous issue for an installation intending to store heat for several months.

This turd hasn't even made it off the ground yet and they're asking for investment money

Oops! This same company already installed a working sand battery two years ago. This is just a larger version of the same technology.

As for heating towns in Finland, geothermal heating is an option that is proven, inexpensive, and available....The geothermal heating plant built by QHeat for Vantaan Energia in the district of Varisto

Sigh, Finland is not Iceland. Geothermal is not widely available throughout the country, and is restricted to a few anomalous sites like Varisto. This research paper will explain why:

"The use of geothermal energy in Finland is restricted ...This is due to geological conditions as Finland is a part of the Fennoscandian (or Baltic) Shield ... Topography is subdued and does not easily produce advective distribution of geothermal heat... rock porosity and its water content are low. This practically excludes geothermal systems utilizing hot wet rock. The lithosphere is very thick in Finland (150-200 km), and heat flow is mostly below continental average (< 65 mW m-2). Measured heat flow density values in the uppermost 1 km of bedrock range from very low (<15 mW m-2) values to 69 mWm-2,... in order to reach 100ºC, depths from 6 to8 km are required. These numbers suggest that Finland is not a good candidate for either wet or dry hot rock systems..."

https://www.geothermal-energy.org/pdf/IGAstandard/WGC/2000/R0778.PDF