Back in 2019, Energy Vault, a startup focused on clean energy, raised a significant amount of funding for its unique technology: a specialized crane that stores clean energy by stacking heavy blocks.

Energy Vault secured a significant equity investment of $110 million from SoftBank’s Vision Fund, which was then the largest investment in a grid storage hardware startup.

Five years later, Energy Vault has not revolutionized clean energy storage with its crane approach. However, the company has demonstrated adaptability and endurance. The company has abandoned the crane design in favor of a larger engineered structure that uses elevators to lift blocks.

Rather than giving up and returning $110 million, Energy Vault invented a large-scale storage device called the G-Vault. This boxy, latticed structure stands at a height of over 300 feet, according to Canary Media.

Heavy blocks are raised using specialized elevators and stored on the upper floors. When energy is required, the building lowers the blocks. The energy released from the lowering of the blocks spins a turbine to generate power.

Effectively, the G-Vault is a battery that stores energy with gravity rather than chemistry.

The first G-Vault is being developed in Rudong, China. Once connected to the grid, the Rudong G-Vault will be the first utility-scale, non-pumped gravity storage system in the world.

Although construction is done, the Rudong project is currently undergoing final commissioning. This involves testing all the components to ensure they are ready for commercial operations.

How the G-Vault gravity battery can reduce curtailment

One of the most impressive features of the G-Vault system is the length of its energy storage capability. Although the Rudong G-Vault will only store energy for four hours (in line with industry norms), the G-Vault system has the potential to store power for up to 18 hours in future projects.

Long-duration energy storage is important because it has the ability to reduce curtailment. Curtailment happens when the power transmission system becomes overwhelmed and cannot handle the surplus of clean energy being generated. As a result, utilities deliberately lower energy production.

According to the Australian Broadcasting Corporation, over 20 percent of renewable energy will be curtailed by 2050.

Curtailment is a disincentive to renewable energy adoption. Curtailment reduces people’s ability to sell excess clean energy to the grid. It also forces them to buy electricity from the grid instead of living off of their own energy output.

Long-duration energy storage reduces curtailment because it increases the grid’s capacity to store surplus energy. This surplus energy can then be deployed when customers need it most.

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