Finland tests a giant battery made of... sand

It's kind of a forbidden topic here at Meio Touch, of batteries, these years of batteries, these revolutionary advances and technologies that will bring an ideal world in six months, if it doesn't rain, so we don't cover these builds up, but in case there is no no advertising. Or revolutionary. Just a good idea.

Philosophically it is a device capable of converting energy in general, in general, to another form. A battery like your Hitachi battery converts chemical energy into electrical energy. A music box stores mechanics, from the winding mechanism.

The main advantage of batteries is that they allow us to access energy quickly and conveniently, the great Achilles heel of energy sources called "green", "alternative" or whatever Greta calls it.

The energy generation curve from sources such as sun powered and wind is not constant, if the rhythm is closed, the generation will drop A LOT in the case of sun based. Storms, calms or even the time of year affect the capacity of wind energy, and to make matters worse, these variations never match the consumption curves.

During the day in most cities general consumption drops, with people on the street working. When they get home, task world turning on air conditioning and miniature waves throws consumption to heights. In the United States, the nightmare of power operators is the last of the Superbowl, with millions of people getting up in the last and using their ovens.

This consumption peak is met by atomic and thermoelectric generation, sources capable of supplying energy on demand, in rapid variations. If we want to abandon thermoelectric generation without increasing an atomic (which would be a mistake, an atomic is by far the best) we have to supply the peak, compensating for what alternative generations cannot.

This is possible with battery banks capable of pouring tons of megawatts into the grid.

These batteries also bring a big advantage: Unlike solar panels, they work overnight, being used on a domestic scale already makes some beat. Tesla itself sells the PowerWall, a unit of batteries that is recharged during the day, when electricity is cheap, and at peak times it powers the house, preventing you from using expensive energy from the grid.

The downside is that doing this on a large scale with Li-ion batteries is prohibitively expensive. What is the alternative? Well, there are several. One of the coolest, obvious, but geographically limited ones is building reservoirs on hills. During the day you use cheap energy from the grid (or alternative sources) to pump water to the reservoir. During the night, you turn on the faucets, the water turns turbines and you get energy at a lower cost than the plug.

There is a little generator made by one of those cool NGOs where a pet bottle with water is lifted by the user (here is a technology blog task world is user) until a certain height, gravity pulls the bottle, which turns a dynamo, charges a battery and lights a lamp. It's little, but enough for a child to study overnight.

Another form of energy storage is mechanical, with equipment that is essentially an electric engine, inside a vacuum chamber. The rotor is designed to be especially heavy. With grid energy, it is accelerated, and as it is in a vacuum, with special bearings hostile to friction, when turning off the electricity, Newton's Laws make it continue spinning, almost without decelerating. The more electrical energy, the more speed, increasing the kinetic energy of the rotor.

If we apply a load to the engine terminals, it turns into a generator, kinetic energy turns into electricity, and the equipment turns into a battery.

There are also devices that store energy in the form of compressed air, in the same scheme: Cheap energy drives the blower, the tank is filled, at night the air is used to turn a generator.

The problem with these devices is that, like Ruby, they don't scale. They are also expensive and constant to maintain. The fewer moving parts the better, and this technique used in Finland by Polar Night Energy is great in that regard.

They decided on the technique of storing thermal energy. Some do this with water, oil and even salt, but dealing with smoke at high pressure is bad and dangerous, and molten salt has the disadvantage of being highly corrosive. Liquid metals either solidify too soon, or boil too soon.

Time needed a material that could withstand high temperatures, up to 1000 degrees, without changing its state or changing its chemical composition. I don't like sand. It's rough, it bothers, it irritates and it gets everywhere, but I'll admit it's excellent for this job.

Sand has been used since time immemorial as a mold for metallurgy, you can pour liquid iron and sand or chuns. Operating system small quartz crystals withstand heat like champions.

Knowing this, Polar's people set up a storehouse with the capacity to store 100 tons of sand. With heaters and heat exchangers, they can heat the sand to somewhere between 600C and 1000C, and with insulation the tank maintains the temperature for months and months.

This equipment, Polar's first in commercial use, was installed at a facility owned by Vatajankoski, a power operator in Kankaanpää, Finland. It can provide 100kW of heating capacity, with a capacity of 8 MWh.

They have a pilot unit in Hiedanranta, with a capacity of 3 MWh, which is being used to provide heating for two buildings, while providing usage and execution data to Polar.

The company says that a large-scale unit would achieve an ostensible power of 100 MW, capacity of up to 20 GWh, with efficiency up to close to 100%. The cost is less than 10 Euros per kWh of stored energy.

After so many amazing projects, so many reinvented wheels and ideas that depend on the use of Inobtanium, Dark Matter and Pink Kryptonite, all mixed with graphene and niobium, it's comforting to see such a... mundane proposal.

It's just an engineering problem, and no engineering problem is unsolvable if you have enough money. Storing energy using temperature is intuitively simple, the Finns themselves are doing this rhythm, heating rocks in bonfires and using them inside their saunas. Using sand is a brilliantly simple jump, with zero toxic equipment, no complexes and that in the event of an accident, the biggest nuisance will be taken away from the local cats by the new public toilet.