Energy Vault

Energy Vault is a global energy storage company specializing in gravity and kinetic energy based, long-duration energy storage products. Energy Vault's primary product is a gravity battery to store energy by stacking heavy blocks made of composite material into a structure, capturing potential energy in the elevation gain of the blocks. When demand for electricity is high, these blocks are lowered with the motors functioning as generators and delivering electricity to the grid.

History

In 2017, Energy Vault was founded by a group of Swiss engineers in the Idealab startup studio.

In 2019, Energy Vault secured funding from Cemex before going on to secure $110m of Series B funding to become the first energy storage investment of the SoftBank Vision Fund, and won Fast Company's World Changing Idea Award for transformative utility-scale energy storage.

In 2020, Energy Vault was Named Technology Pioneer by World Economic Forum and completed the mechanical construction of the first of its kind, grid-scale testing tower in Castione-Arbedo, Ticino, Switzerland.

Testing tower operation and potential

In 2019, construction of a testing tower for the case study EV1 started in Castione-Arbedo, Ticino, Switzerland. It is about 70 m high and each of the 3 double cranes up to 66 m wide. The blocks made of cement with fly ash have a mass of 35 tonnes each. In December 2020 single blocks were raised and lowered 42 m over about 1 minute at 0.7 m/s and the energy drawn from and returned to the national grid recorded. 4.124 kWh electricity was needed to achieve the maximum theoretical potential energy of 3.906 kWh at this height, giving ~95% efficiency for this. On lowering a production of 3.106 kWh was recorded, giving a mean production power of ~186 kW and an efficiency of ~79.5% for this, giving a total round-trip efficiency of ~75%.

A photograph shows about 28 blocks available at the lowest level. With the blocks each weighing ~340 kN and measuring assumed 5 m in height, a potential energy of 340 kN x 5 m = 1.7 MNm = ~0.47 kWh can be stored for each block raised one level. The January 2022 photograph on this page shows 8 blocks standing on the second level, 4 on the third level, and 2 on the fourth and final level. They are thus totally storing 1.7 MNm x (8 + (2 x 4) + (3 X 2)) = 37.4 MN = ~10.4 kWh.

The dimensions of the tower allow stacking at least 8 layers. The base layer stores no energy. If the active 7 layers above have 28 blocks each, with each layer weighing ~9.5 MN, and each block can each be lowered to the ground outside the original base layer, the second layer can be lowered one level assumed 5 m, the third 10 m, the fourth 15 m, and so on. This gives a sum of 140 m x 9.5 MN = 1330 MNm = ~370 kWh. With 9 layers it would be 476 kWh.

The stacking method actually envisioned for EV1 shows outside circular layers concentric to the inner one with roughly twice its diameter. This is built up to a height about one third of the inner one. The maximum height difference of the total centers of gravity of the two stacks is then one third of the maximum height. In the testing tower this would be 14 m. The maximum energy storable would then be 7 x 9.5 MN x 14 m = ~931 MNm = ~259 kWh. This is under 1% of the 35 MWh goal for EV1.

The full size EV1 would have 7000 blocks of 35 t. Drawings show 36 layers with 200 blocks each, totaling 7000 t for the inner stack. The bottom 14 layers are not actively usable. The upper 22 layers with a total mass of 154 kt weighing ~1510 MN are moveable and assuming 5 m high blocks have their center of gravity at 125 m height. When they are all lowered and displaced to form an outer ring, their center of gravity is then at 35 m. Therefore the average drop is 90 m and the maximum energy storable 1.51 GN x 90 m = 136 GNm = 37.8 MWh without counting friction and conversion losses.

Further company development

In 2021, Energy Vault announced investments from Saudi Aramco Energy, and other existing investors.

In February 2022, Energy Vault Holdings, Inc. began trading on the New York Stock Exchange following the business combination with Novus Capital Corporation II that raised approximately $235 million in gross proceeds additive to $107M and $50M license fees from Atlas Renewable. Atlas renewable being a subsidiary of China Tianying Inc, a company with core activities in energy production from waste processing.

First generation of commercial gravitational batteries

China

The association with Atlas renewable quickly leads to a licencing agreement with chinese construction companies and local autorities to build a couple of streamlined energy vaults in Rudong (China), next to one of China Tianying's windfarms.

In the summer of 2023, the company announces starting commisionning of its first 25 MW/100 MWh battery in Rudong. A couple of month later, China Tianying announces a planned capacity upgrade up to 3.3GWh.

Technological diversification

As gravitational batteries seems to target very narrow use cases, the company extended its activities to other electricity storage technologies.

Electrochemical batteries

Energy vault's AI powered storage & demand management software is also being leveraged in the BESS (battery energy storage system) sector through its B-Vault product line, which is proving quite successful in the US and worldwide (According to its 2025Q1 Financial Results, the company also generates revenue from BESS licencing agreements in India and Australia while being implemented through owned / operated sites in the US).

Another solution bootstrapped by the company is a mixed backup solution combining hydrogen fuel cell and battery powered buffer for frequently off-grided areas, with a prototype installation in Calistoga (Florida).{{cite web , title=Napa Valley town that once rode out emergencies with diesel gets a clean-power backup , publisher= The Associated Press , url=https://apnews.com/article/california-wildfires-calistoga-energy-vault-hydrogen-batteries-2949e405ac9ce5e52eff835d2fbd4c10 , access-date=16 June 2025 , date=4 June 2024

References

Energy storage
companies based in Ticino
Companies listed on the New York Stock Exchange