SAND BATTERIES:
Not every technology bettering our future has to be complicated, some are simple, yet extremely effective.
One of these kind of technologies has come from some Finnish engineering who have found a way to turn sand into a giant battery.
These engineers piled 100 tons of sand into a 4 x 7 meter steel container. All of this sand was then heated up using wind and solar energy.
This heat can then be distributed by a local energy company to provide warmth to buildings in nearby areas. Energy can be stored this way for long periods of time.
All of this occurs through a concept known as resistive heating. This is where a material is heated by the friction of electrical currents.
Sand and any other non-super conductor are warmed by the electricity passing through, the generated heat can be used for energy.
What Is a ‘Sand Battery’?
A“sand battery” is a high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat.
Sand battery is a high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat.
Its main purpose is to work as a high-power and high-capacity reservoir for excess wind and solar energy. The energy is stored as heat, which can be used to heat homes, or to provide hot steam and high temperature process heat to industries that are often fossil-fuel dependent.
As the world shifts towards higher and higher renewable's fraction in electricity production, the intermittent nature of these energy sources cause challenges to energy networks. The sand battery helps to ambitiously upscale renewable's production by ensuring there’s always a way to benefit from clean energy, even if the surplus is massive.
The first commercial sand battery in the world is in a town called Katakana, Western Finland. It is connected to a district heating network and heating residential and commercial buildings such as family homes and the municipal swimming pool. The district heating network is operated by an energy utility called Vatajankoski.
The term “sand battery” was introduced to the grand audience by a BBC News story published the 5th of July 2022. The story was written by BBC News’ Environmental Correspondent Matt McGrath.
Why do you use sand?
Many solid materials, such as sand, can be heated to temperatures well above the boiling point of water. Sand-based heat storage can store several times the amount of energy that can be stored in a water tank of a similar size; this is thanks to the large temperature range allowed by the sand. So, it saves space, and it allows versatile use in many industrial applications.
How hot is the sand?
The maximum temperature in the Katakana, heat storage, is about 600 degrees Celsius. However, the temperature may even be higher depending on customer needs. In practice, the maximum temperature of a sand-based heat storage is not limited by the properties of the storage medium, but by the heat resistance of the materials used in the construction and control of the storage.
How is the heat storage insulated?
The heat storage is made of steel and insulated with standard, heat-resistant insulating materials. The insulation is all around the heat storage between the outer steel layer and the inner one.
How hot is the sand?
It can stay hot for months if needed, but the actual use case of the heat storage in Katakana is to charge it in about 2-week cycles. The heat storage has its best range of use when it is charged and discharged 20 to 200 times per year, depending on the application.
Can it store electricity?
Not as such, as it stores energy in the form of heat. The heat can be converted back to electricity using turbines like the ORC-turbine or a steam turbine. This requires additional investments to the turbine technology, and the conversion to electricity has inherent losses, thus complicating the economical side.
Is this a new technology?
Well, yes and no. The idea of heating sand to store energy is not new. Our way of doing things and commercializing it in large scale applications is.
Can I buy your heat storage for my house?
No. We don’t have products for individual homes yet.
You must be logged in to post a comment.