Sand is a natural resource that has widespread applications in diverse sectors and industries. But engineers in Finland have put sand to a quite unique use and created the world’s first sand battery that can store energy for months. The researchers believe that the invention could resolve the issue of ensuring a year-round supply of green energy, which is a major limitation of transitioning to total reliance on renewable energy sources.
The science and other stuff to know
The first sand battery has been installed in the Finnish town of Kankaanpää by a company called Polar Night Energy. Markku Ylönen, one of the founders, told BBC their aim was to create a usable reservoir for green energy.
“Whenever there’s like this high surge of available green electricity, we want to be able to get it into the storage really quickly,” Ylönen said.
The massive sand battery is shaped like a grain silo and is connected to the Vatajankoski power plant that provides heating for residential and commercial buildings. The silo, or battery, contains around 100 tons of builders’ sand. This giant pile of sand is heated to up to 500oC (932oF) using wind or solar energy.
The cheap electricity warms the sand through resistive heating, creating hot air that is circulated through the sand pile using a heat exchanger.
Sand is an effective medium for conserving heat and is almost immune to energy loss, hence Polar Night Energy’s claims that the battery could maintain the 500oC temperature for several months.
The stored heat could then be used to produce hot air that can be utilized to warm homes or heat water in the harsh winter that descends on Finland each year.
While renewable energy sources are the most sustainable answer to climate degradation caused by non-renewable sources of energy, their limited availability is a serious issue. The sun cannot shine throughout the day, and neither can the wind blow continuously to keep the windmills going.
Conventional batteries currently used in small and large applications consist of toxic materials like lead and lithium, and scaling them to store large amounts of energy would be an extremely expensive and almost impossible procedure. The sand battery, therefore, is a considerably low-cost alternative that requires simple raw materials and is friendly for the environment in every way.
The novel concept of a sand battery is not only environmentally friendly, but it is also a great way to reduce the cost of obtaining energy in winter when it becomes twice as expensive to do so.
The battery could be an excellent option for various industries whose core manufacturing processes depend on heat, which can only be produced through the continued burning of fossil fuels. A sand battery like the one in Finland could offer a sizable reservoir of energy and drastically reduce the cost of production for various industries.
However, it remains to be seen if the technology can be scaled to accommodate a larger purpose and be made ready for widespread use. We are keeping our fingers crossed for this one.