The idea of storing energy in the mountains through the use of sand drew attention due to its environmental aspect, but it may be possible to dispense the mountains from the equation with this new method of storing renewable energy.
Renewable energy is a great option in a world in which environmentally friendly solutions are increasingly emerging, but what can we do when the sun doesn't shine and the wind doesn't make itself felt? THE Energy Vault seems to have found the solution.
The Achilles heel of renewable energies is, precisely, the difficulty in storing energy. Robert Piconi, CEO of Energy Vault, explained that the search for a solution started two years ago, when the company chose not to invest in known technologies, such as batteries, to store electricity.
"These types of solutions require the use of chemical or metallic substances, such as lithium, substances that have a strong impact on the environment", he said, adding that the efficiency of the batteries decreases with time.
The solution found by the company consists of a giant tower of cement blocks, each weighing approximately 35 tons. In LEGO style, a six-arm crane integrated in the center moves the blocks from top to bottom, using renewable energy.
During the downward movement, caused by the gravitational force, the stored energy is converted into electrical energy, without any loss of energy. According to the Swiss Info, software automatically controls the loading and unloading process in the tower, and takes into account factors such as wind, which can have an effect on the blocks.
This system is similar to the principle of reversible hydroelectric plants, which take advantage of the height difference of two hydrographic basins. In relation to these plants, the block tower has an advantage: it can be built anywhere. In addition, prices are very low and the degree of energy efficiency is 80%, explains the official.
According to the company, a 120-meter-high tower can store up to 35 megawatt-hours (MWh), enough to supply two to three thousand homes for eight hours.
In November, Energy Vault submitted an order to build a prototype: a 60-meter-high tower on the outskirts of Bellinzona, Switzerland. The construction will allow to optimize the software and the cement block movement processes.
If the test is successful, the product could be launched on the market as early as 2020.