As renewable energy technologies join the grid more and more, the problem of the wind or sun’s inability to produce electricity continues to be an obstacle that increases its effect. In other words, we must either make a storage technology economical that will regulate non-regular production, or increase the transmission capacity between countries by switching to extremely high production capacity.
In the end, countries can benefit from each other, as a scenario without wind or sun in the whole of Europe will not be a reality. Another solution is to efficiently store as much as we can. Overproduction has already started to cause problems in the grids in some cases. In Europe, negative prices or free electricity prices do not occur at certain hours or days due to incentives.
As such, it is very important to store electrical energy as heat among the easiest and cheapest storage methods. The easiest way to make this cheap battery is to make it from the cheapest material. The Finnish company Polar Night Energy has achieved this with sand, air and resistance.
The battery simply draws electricity from the grid at very cheap times. It uses it to heat the air and, with the effect of the air, to heat the sand. The system raises the temperature of the sand up to 500 degrees Celsius. It then uses this energy in the heating network. Thanks to the heat networks, which are quite common in Europe, thousands of houses are heated from one floor and many savings are achieved. Users also pay bills for the heat they use.
The project, which was initially taken to support the grid, has a 100 kW heater and a total energy capacity of 8 mWh. The company plans to reduce the temperature to 1000 °C and the kWh storage cost to below 10 Euro/cent in the future. Thanks to its high thermal insulation, it can be stored for months and returned with 95% efficiency. Thanks to its durability, it can be used for decades with minimal maintenance. Capacity values can be scaled from 100 MW power to 20 GWh total storage capacity without using any substances that may be harmful to the environment.
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