How is the sand energy battery?

The lack of conventional energies that Europe suffers is patent and it has been shown in an alarming way with the cut off of gas supply by Russia. This has been in response to the economic sanctions that the European Commission and its member countries have imposed on the former Soviet republic, before the invasion of Ukraine.

Europe had already set itself the goal of achieving an energy model without fossil fuels or, better said, use only renewable energies. This means that, in order to reduce the electricity pricemultiple solutions have been investigated for some years.

The answer to the energy problem that we explain today has been designed and successfully tested by a team of Finnish engineers. And for this they have employee just sand. How is it possible? Can sand be an energy battery?

Origin of the idea for the sand battery

To put ourselves in a situation, we must understand that Finland is a country with a long winter. When the hours of sun they are minimalDue to both the short duration of the day and the constant presence of clouds, photovoltaic plants hardly generate electricity in this season, when electricity is most needed. In addition, in the worst of winter there is hardly any wind that can be used by the wind turbines.

Finland had also belonged to the Russian empire of the tsars. With the revolution of 1917, the Lappish peoplewho felt different and detached from Moscow, requested and got its independenceconstituting itself as a new country detached from Russia.

Since its independence, it has had constant disputes with the Soviet Union first and with Russia later since its creation. So much so that, in 1939, Stalin ordered the invasion of Finland, after refusing the installation of Soviet military bases on its territory. As a result, the Nordic country lost its easternmost region to the USSR, although it retained its independence.

It is because of that, after the Russian invasion of Ukraine, the Lappish country has decided to apply to join NATO, motivated by his fear that Russia will try to invade again. In response, Putin has cut off oil and gas supplies to Finland, leaving this country in a complicated energy situation.

It is here where there is a great need to find alternative forms of energy and, above all, how to store it to use it in the dead of winter.

How does the sand battery work?

The sanddue to its physical and chemical characteristics, is capable of heating up to 1,000 °C without changing your physical condition. Also, the accumulated heat gives it up very slowly, and more if it is confined within a properly insulated container.

The Finnish researchers rightly thought that, if they used the renewable energy left over in the summer to heat a sand deposit, it would conserve the heat so that it could be used in the winter. Thus, the surplus produced by renewable energy plants, such as wind power, photovoltaic or the tidal wave, to heat sand.

The sand tank resembles a heat exchanger. In other words, the container has inside a network of pipes through which air is circulated. On the one hand, the sand is heated by the Joule effect, converting surplus electricity, that is not consumed by citizens and industries, in heat.

Then, when heat energy is needed for some industrial process or for heating, air is circulated through the pipe network. East air is heated to temperatures of hundreds of degrees centigrade and is used to heat water that will be used in heating or in the textile, food or other industries.

In much of Finland, home and building heating is centralized. Water is heated in thermal power plants and water or water vapor is distributed through buried pipes. That is why this system has a direct application. These sand batteries can be built next to central heating and take advantage of them in winter, when energy is more expensive.

Sand battery to generate electricity

With the sand battery that Finnish engineers have developed and successfully tested is achieved store up to 8 MWh of energy, although they consider that it is possible to increase it to 20 GWh. At present, this accumulator has a heat output of 100 kWhowever, this amount can also be increased considerably.

Although for the moment the design only allows its use to heat water and its use in thermal processes or heating, the researchers plan to go further. The idea is to get the sand battery to accumulate heat and that this heat can convert directly into electricity, so that it can be used anywhere and need, not only as heat energy.

That is why Finnish and American researchers continue to work to get a sand battery that can give us electricity, substantially improving current possibilities with lithium batteries.

Advantages and disadvantages of the sand battery

Like all new developments to generate and store energy, we must weigh its pros and cons to decide if it is a viable alternative, both economically and ecologically.

Advantage:

1. Take advantage of surpluses

The idea is to take advantage of the surpluses of wind farms, photovoltaic orchards or others of renewable origin and on which we do not have the capacity to decide when to start them. Unfortunately, the wind doesn’t blow when we want and the sun doesn’t shine at night.

2. Economic accumulation

Sand is a relatively cheap material and the design of the battery does not require complicated technologies, so the total cost of the battery is not excessively expensive. Above all, if we compare it with the energy that it can accumulate and other types of storage.

3. Ecological

Both the materials used in its construction, and the operation itself, do not generate pollution. During the heating of the sand, no fumes, carbon dioxide or other gases are released.

4. Recyclable

Unlike large lithium batteries, sand batteries can be recycled easily and at minimal cost. No polluting or dangerous waste is generated.

5. Adaptable to any place

The simple technology you need makes it possible to build sand batteries where there is surplus energy, which can be consumed later. In addition, the size of the battery can be adapted to the circumstances of each place or surplus energy.

drawbacks

1. Young technology

The sand battery has only just been born and, although it has been successfully tested, it is clear that it still has a long way to go before it works to its full potential.

2. Scarcity of sand

Sand is a cheap material and there is a large quantity. This is both an advantage and a drawback, since it makes it the second most exploited material or element on our planet, after water.

In addition, there is no regulation that controls the extraction and exploitation of sand, so its use is done without thinking about the environmental damage that is generated.

Faced with this problem, the Finnish researchers say that other materials similar to sand can be used, with which the problem of its scarcity would be solved.