Heat is the biggest end use for energy all over the world. It's also critically important for survival in a country like Finland where the winter is long, cold and dark. And the recent move by Russia to cut off supplies of gas and electricity in response to Finland joining NATO has caused concern.
There is good news, however, that the world's fully first working sand battery has been installed in Finland. It is a device which can store sustainably produced heat for months at a time and can be used to keep homes warm in winter. That's why the new technology was developed by researchers there. Researchers believe it can solve the country's year-round crisis in power supply, which is a significant issue for green energy.
The sand battery was installed in the Vatajankoski power plant that runs the heating system for the houses in the area. It works by heating the sand, circulating the heat generated in the sand using a heat exchanger. Researchers used low-grade sand to charge the devices with heat from cheap electricity coming from either solar or wind energy. The sand battery can store energy and heat up to 500 degrees Celsius. which can be used to warm homes during winter when electricity is more expensive.
It is a cost-effective method because when the battery releases the hot air, it warms the water for the district heating system that is pumped around homes, offices, and the local swimming pool. Sand is an ideal material because it is cheap and readily available everywhere. While other inexpensive items like water can store heat, sand can be heated to much higher temperatures. The sand used is of the lowest quality so it cannot be used in construction thus making it a sustainable choice. Besides, sand-based batteries last longer than other batteries. According to a study, researchers obtained silicon using sand to create a battery that lasts three times longer than lithium-ion(锂离子) batteries.
"This innovation is a part of the smart and green energy transition. Heat storage systems can significantly help to increase intermittent (间歇性的) renewables in the electrical network," said Markku Ylönen, cofounder of Polar Night Energy. "At the same time, we can make full use of the heat waste to keep the city warm."
