According to Techspot, the system is called Lift Energy Storage Technology (LEST) and it can make use of existing elevators, so there's no extra cost of replacing them.

The elevators can be moved even without humans in them, as automated machines can load and unload high-density materials to transport them up and down, generating more energy in the process.

This can be achieved through the use of regenerative braking, which is more effective if the load is heavier and the energy can be stored for later use.

Researchers say that there are around 18 million operating elevators in the world, and more often than not, they sit still, so the energy-generation potential is high.

Julian Hunt, lead author of the study, said that he got the idea when he went on a 14-floor elevator ride one day, wondering if we could be able to generate power from riding elevators every day.

There are a few challenges when it comes to building a system like this, such as the weight that the top floor can support, considering the regenerative braking system and the energy storage system, which needs its own space and weights extra as well.

Still, the idea is innovative and we could try at least to adapt it in order to generate some extra power from a process that's already happening a lot of times per day everywhere in the world.