The Renewable energy (wind, solar, etc.) intermittentthat is, it is not always available when necessary and that is why many solutions have been created for itenergy accumulation and his Release when actually requested. There are many approaches, with their own advantages and disadvantages in terms of costs, efficiency and footprint, but there is one you can all agree on: Energy accumulates in the form of heat in the sand.
to suggest this solution polar night energywhich is a Finnish reality that just exists The first commercial sand-based plant opened To accumulate high temperatures together VatajankowskiThe local reality of the electricity sector. The electricity stored in sand comes in the form of heat Used for central heating network From Vatajankoski in the city Kankanbein western Finland.
Markku Ylnen, Co-Founder and CTO of Polar Night Energy, explained that creating this innovative solution went well and The The system showed greater potential than initially calculated. Heat accumulation is represented by Steel container 4m wide and 7m high which is inside Hundreds of tons of electrically heated sand produced by solar/wind installations.
there sand used, of low quality, represent Long lasting and inexpensive material A lot of heat can be stored in a small volume.
In the case of this first plant, The sand is heated to about 500-600°C (The temperature can be stay for several months and exceeded, reaching more than 1000°C) heating resistance (The same process that makes electric stoves work).
This solution is born Hot air circulating in the sand by a heat exchanger. The heat in question is then released into an area heating station during the freezing Finnish winter where the sun’s rays are an illusion for several weeks. This way in the town of Kankanbe residents can Thermal houses have hot water and even maintain a good temperature in the communal pool.
The complex installed in Finland can store well 8 megawatt-hours of power, nominal capacity of 100 kW. According to Polar Night Energy, the system features Efficiency factor up to 99%The ability to store heat with minimal losses for months and a lifespan of up to decades. In addition toI Installation costs less than 10 euros per kWh It works independently and at minimal cost.
The company is now aiming to increase the capacity of this plant: the goal is to move the installations forward by about 20 GWh to produce hundreds of megawatts of nominal capacity using sand heated to 1,000°C.