Stones the size of a hailstone heated to 600 ° C in large insulated steel tanks are the centerpiece of an innovative project that aims at the storage of wind and intermittent solar energy.
The technology, which stores electrical energy in the form of heat in stones, is called GridScale and could become a cheap and efficient alternative to storing solar and wind energy in lithium batteries.
Energy storage in stones
While the car's battery performance lithium batteries are only convenient for supplying energy for short periods up to four hours, a storage system such as GridScale will support the supply of electricity for longer periods, up to about a week.
The problem with a 100% renewable electricity supply is that you cannot save the electricity generated for later use. Our storage system can be a solution.
Henrik Stiesdal, founder of the company of the company that developed GridScale, Stiesdal Storage Technologies
What is GridScale
In short, GridScale technology is about heating and cooling crushed basalt into tiny bead-sized stones in one or more sets of insulated steel tanks. The storage facility is loaded with a system of compressors and turbines, which pumps thermal energy from one or more storage tanks filled with cold stones to other storage tanks filled with hot stones, when there is excess energy from the wind or sun.
This means that the stones in the cold tubs become very cold, while they become very hot in the hot tubs: as mentioned, up to 600 ° C. The heat can be stored in the stones for many days and the number of tanks filled with stones can vary, depending on the required storage time.
When there is new demand for electricity the process is reversed: the stones in the hot tanks become colder and vice versa. In summary, the system is based on inexpensive storage material and mature, well-known technology for loading and unloading.
Basalt mon amour
Basalt is a cheap and sustainable material that can store large amounts of energy in small spaces. It is a stone resistant to countless charges and discharges of the storage facility. We are developing a prototype that could solve the renewable energy storage problem, one of the biggest challenges to sustainable energy development worldwide.
Ole Alm, development manager at the energy group Andel, partner of the project
The GridScale prototype will be the largest storage facility in the Danish electricity system with a capacity of 10 MWh. The location is still in progress: there is a run-off between the eastern (so-called southern Zealand) or western (Lolland-Falster) part.
The energy transition will change the functioning of the entire energy system. The reasons? Simple. Solar and wind energy are not produced at the same time as we may need them.
This is why storage and the mix of energy technologies are essential. I think stone-based storage could really have enormous potential.
Further details
The full name of the project is “GridScale – cost-effective large-scale electricity storage”. It will last three years with a total budget of 35 million Danish crowns (4,7 million euros). It is financed with 21 million crowns (2,8 million euros) from the Energy Technology Development and Demonstration Program (EUDP). In addition to the companies Stiesdal and Andel, partners include the University of Aarhus (AU), the Technical University of Denmark (DTU), Welcon, BWSC (Burmeister Wain Scandinavian Contractor), Energi Danmark and Energy Cluster Denmark.
