A Battery Made Out of Sand?
Updated: Aug 18, 2022
Technology Never Ceases to Amaze Me!
To put this all simply, Polar Night Energy wants to upscale solar and wind energy to meet everyone’s heating and electricity demands. To achieve this, they patented high-temperature, large-scale heat storage.
In Polar Night Energy’s own words:
WE USE REALLY, REALLY HOT SAND AS THE STORAGE MEDIUM
Polar Night Energy takes sustainable electricity from solar and wind power (above) and converts it to heat stored in 100 tons of sand for later usage. They found the best way to keep this heat was with sand. Since sand is plentiful and can be heated to extreme temperatures (600 degrees C), it has become the perfect storage means.
The magic is all in the heat transfer system within the sand. They can transfer to and from with minimal heat losses due to the enhanced insulation between the environment and the storage container. Even more exciting, this heat can be stored for months and potentially longer when the heat is needed.
The most exciting part of this technology is that it is already being used. The first commercial sand battery in the world is in a town called Kankaanpää, Western Finland, and it is used in district heating providing heat to homes, offices, and even swimming pools.
Most cities are already equipped with district heating, and Polar Night Energy aims to connect to this existing system and provide heat. So what exactly is district heating? As defined by districtenergy.com
District heating is an underground infrastructure asset where thermal energy is provided to multiple buildings from a central energy plant or plants. Steam or hot water produced at the plant is transmitted 24/7 through highly insulated underground thermal piping networks. The thermal energy is transferred to the building’s heating system, avoiding the need for boilers in individual buildings.
You will find district heating in densely populated cities like New York City.
The only absolute requirement for the sand is that it must be dry; otherwise, Polar Energy is looking to use the sand most people don’t want, which keeps the cost low. Again, this is just sand with no special treatment to something already in great abundance.
The actual cost will be in the larger systems and the piping. Smaller systems will be designed with smaller steel cylinders, mostly assembled above ground (pictured below)
As the systems scale up, the larger sand batteries could be stored underground or in canyons. If stored underground, structures could be built atop to utilize the space above. It is also important to note that the larger the system, the more energy efficient they become.
I expect the technology to evolve over the next couple of years. How long before they perfect the type of sand used to utilize the battery’s capabilities? They currently store the energy captured from renewables as heat but are actively looking for ways to convert this back to electricity efficiently to utilize the system. The next few years will tell the story of this new yet simplistic form of storing heat.