When you think of energy solutions, you might not imagine that 100 tons of construction sand is piled up in a huge silo. But one company has found that sand can be the secret sauce for energy storage, as it can store heat for months.
How does this work?
Finnish startup Polar night energy has developed a new way of storing heat.
A 4×7 meter steel container is filled with hundreds of tons of sand. The sand is then heated with wind or solar energy and stored for use by a local energy supplier to heat the local neighborhood. It is in fact a giant sand battery.
While wind and solar are extremely useful, they only provide intermittent power. Watch what this means in the video below:
On the other hand, sand is durable and cheap and can store a lot of heat at a temperature of about 500-600 degrees Celsius without dissipating.
This means that once heated, the silo can stay warm for months with minimal intervention.
In concrete terms, the system can discharge a maximum of 100 kW of cogeneration and has a total energy capacity of 8 MWh.
The company’s sand battery is currently heating the Kankaanpää district, keeping homes, offices, factories and the local swimming pool warm.
Not only a solution to a problem, but also commercially viable
Polar Night Energy was founded in 2016 by two university graduates who are well versed in thermal energy. They only have raised 500k in seed capital†
The challenge is that there is no shortage of innovation in renewable energy with a lot of R&D in academia. But bringing an idea from the hyperfocus University environment to real commercial applications is where many startups fail.
But the company has managed to go hyper-local. They have partnered with energy supplier Vatajankoski and gained local government traction to supply district heating†
And they struck at just the right time to solve a local problem.
Many homes and businesses are faced with fuel poverty by rising gas prices. Russia cut off Finland from its gas supplies for refusing to pay in rubles. Not good news for Finland, a country with long, cold winters.
But through their successful collaboration, Polar Night Energy is a great example of how creativity can solve complex environmental and social problems.