Australia is poised to tap the Snowy 2.0 hydro pump project that is set to become operative in six years at an estimated cost of around $4 billion. The technology involves water pumped uphill and released to turn a turbine under gravity.
Hydro pump technology reportedly accounts for 96 per cent of the world’s energy storage capacity.
However, Swiss company Energy Vault has devised what its founder believes is a much simpler, cheaper technology to store and retrieve energy – by lifting concrete blocks against gravity and letting them fall, according to European publication Quartz.
The theory behind it is concrete is a lot denser than water, and hence a block of concrete when lifted can store a lot more energy than a tank of water of the same dimensions.
When supply is low, the crane’s motors run backwards when the blocks are dropped to release energy back into the grid.
The company unveiled a demonstration plant in Biasca, Switzerland, close to Milan, Italy. The plant was formulated and up and running in nine months – for as little as $USD2 million ($AUD2.73 million).
Energy Vault is cutting costs by using off-the-shelf hardware, and is now designing software to automate the crane’s actions and counter the movement of blocks in crosswinds, making it smoother and more efficient.
Furthermore, the plant is claimed to be an environmentally friendlier project that manufactures concrete blocks using recycled building materials or gravel rather than virgin materials.
Unlike pumped hydro, this system doesn’t require dams or water. The concrete block system offers 85 per cent more efficiency when compared to pumped hydro, placed between 70 and 80 per cent.
The new system also needs minimal maintenance and has the ability to operate for 30 years at the same capacity.
The blocks, however, have to be manufactured on-site, and a 35 megawatt per hour system would require a circle of land 100 metres in diameter.
Energy Vault’s chief technology officer Andrea Pendretti said the system’s niche will be in places with no shortage of land and building material.
Parts of Asia and Africa would hence make the concrete block systems a good option for renewable energy storage.
The demonstration plant in Switzerland is a scaled-down model of the commercial plants that have been commissioned to be built in 2019.