With the development of renewable energy sources, it is necessary to find a way to store energy efficiently, due to its unstable nature. This is why many concepts were created, yet most of them being pretty expensive investments. It turns out that already existing skyscrapers can help. This would be achieved by means of elevators, robots and empty apartments.
Gravitational energy storage is a well-known concept. However, scientists have figured out a way to use skyscrapers and abandoned apartments for this purpose.
The idea seems simple. The “Lift Energy Storage Technology” system developed by Julian David Hunt’s team, in which Dr. Eng. Jakub Jurasz from the Wrocław University of Technology and dr inż. Paweł Dąbek from the University of Life Sciences in Wrocław, assumes the use of the existing lifts and apartments for energy storage in the form of transporting loads to high floors.
The assumption is that lifts will transport high-density products, such as wet sand, when the generation of electricity from renewable energy sources is high. Transporting the load upstairs would consume the electricity produced. On the other hand, lowering the charges would generate energy.
Cargo transportation would take place when the lifts are not used by people. What to do with the loads when they are at the top? The idea of scientists is that they will be stored in empty premises in high-rise buildings. Autonomous robots would transport them to them.
The issue with this project appears to be cost effectiveness. The mere use of existing infrastructure makes this storage concept quite cheap. On the other hand, problems may concern, for example, the durability of buildings. There is a risk that a significant weight on high floors would translate into damage to ceilings or walls.
For 5,000 containers with dimensions of 0.5 by 0.5 by 2 meters, 5 thousand. tons of sand and for ten autonomous robots the cost of the project would oscillate around 70 thousand. dollars. In terms of kilowatt hours, that’s $ 64 per kilowatt hour. A typical battery will cost $ 120 per kilowatt hour.
Further development of the concept may make it profitable. However, it should be taken into account that the costs of operating such a warehouse include, for example, the price of renting empty apartments for storing containers, or possible costs related to the redevelopment of the premises. The idea itself seems to be interesting, however, and would be an alternative to classic energy storage systems.