How does Energy Vault work?

Energy Vault has created a new storage system in which a six-arm crane sits atop a 33-storey tower, raising and lowering concrete blocks and storing energy in a similar method to pumped hydropower stations. How does the process compare to other forms of energy storage, such as batteries and pumped-storage hydro?

How efficient is Energy Vault?

The ramp rate for Energy Vault’s gravity storage solution is as little as one millisecond, and the storage system can go from zero to 100% power in no more than 2.9 seconds. Furthermore, the system has round-trip power efficiency, i.e. zero to full power to zero, of 90% efficiency, meaning only 10% energy loss.

How much does energy vault cost?

In contrast, Energy Vault’s gravity storage units cost around $7m-$8m to build, and have a lower levelised storage cost of electricity, which measures on a per kWh basis the economic break-even price to charge and discharge electricity throughout the year. It is considered by some to create a more accurate measurement of energy costs.

What is the difference between a pumped hydro plant and Energy Vault?

“Pumped hydro plants have a round-trip efficiency of around 70%, whereas the Energy Vault system has a round-trip efficiency of between 88%-92%, which allows for a greater energy storage capacity and thus fundamentally better economics. Can it compete in the long term?

Why did PG&E choose Energy Vault?

Utility PG& E separately chose Energy Vault to provide clean backup power for the town of Calistoga when wildfire risks prompt power shutoffs. The assignment was to provide at least two days’ worth of power without the broader grid, and at a lower price than trucking in mobile diesel generators.

Why do cranes have a low power-to-energy ratio?

The “ fundamental issue” that did it in, according to Chief Product Officer Marco Terruzzin, was the power-to-energy ratio. The blocks equate to energy capacity, but the number of crane arms limited how many blocks the system could let down at once, thereby restricting the instantaneous discharge capacity.