energy vault

Gravity storage on the grid

June 4, 2024 By EarthWise Leave a Comment

For the past several years, the Swiss-based company Energy Vault has been developing an energy storage system based on the principle of using mechanical devices to lift heavy concrete blocks into stacks using power generated by wind turbines or other renewable sources. When energy is needed, the blocks are lowered back to the ground, spinning generators in the process.

The principle of storing energy in the form of gravitational potential energy is the most widely used form of energy storage in existence but usually works by pumping water into a reservoir at higher elevation and then letting the water come back down when energy is needed.

Energy Vault has built a grid-scale 100 MWh gravity storage system in Rudong China. It has now been successfully tested with charging and discharging and has been commissioned. Pending final provincial and state approvals, it will be the world’ first commercial, utility-scale non-pumped hydro gravity energy storage system.

The Rudong project teamed Energy Vault with environmental management company CTNY and Atlas Renewable. Energy Vault has extended its license agreement with Atlas Renewable to 15 years. CTNY has announced plans for eight additional deployments of the Energy Vault gravity storage system across China, representing more than 3.7 GWh of energy storage.

Energy Vault’s technology has attracted a fair amount of skepticism from parts of the energy community based on the environmental burdens of concrete as well as durability issues. It appears the technology will have significant real-world testing in China, which should provide unambiguous answers to everyone’s questions.

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Energy Vault Announces Successful Testing and Commissioning of First EVx 100 MWh Gravity Energy Storage System by China Tianying, Extension of Atlas Renewable Licensing Agreement to 15 Years

Photo, posted December 21, 2018, courtesy of Nancy Winfrey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Grid-Scale Gravity Energy Storage | Earth Wise

September 19, 2023 By EarthWise Leave a Comment

As wind and solar energy play a growing part in our energy system, the need for grid-scale energy storage is growing as well. An historic form of energy storage and still the largest in installed capacity is pumped hydro storage, which makes use of the potential energy contained in having water sitting at a higher elevation where it can be released downward to operate turbine generators. This is an effective system but is limited to places where geography cooperates.

For the past five years, a company called Energy Vault has been developing a system that uses the same principle to generate electricity but instead of pumping water to a higher elevation, it uses mechanical devices to lift heavy objects such as concrete blocks to an appropriate height. Lowering the blocks back to the ground drives generators.

To date, Energy Vault has only built demonstration systems with a fraction of the storage capacity needed for grid-scale operation. Their EV1 Tower in Switzerland was successfully grid interconnected in 2020 and demonstrated round-trip efficiency (the fraction of the energy stored that was produced by the generators) above 75%. Their improved EVx system is expected to do better than 80%.

This year the company, along with partners Atlas Renewable and China TIanying, is now in the first phases of commissioning a grid-scale system located outside of Shanghai, China. The 25-MW system is built adjacent to a wind farm and a national grid interconnection site

This is the first grid-scale gravity energy storage system and is expected to be fully online in the fourth quarter of this year. A second, similar system is now under contract to be built elsewhere in China.

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First grid-scale gravity energy storage system undergoes commencement in China

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio

Major Funding For Novel Energy Storage | Earth Wise

October 21, 2021 By EarthWise Leave a Comment

The accelerating adoption of wind and solar energy is driving a growing interest in energy storage technologies. An electric grid dominated by intermittent power sources will need large-scale energy storage. Grid-scale energy storage is expected to increase at least 10 times over the next decade and this will require nearly $300 billion in investments over that time period.

Much of the effort in energy storage has focused on battery storage. But there are other storage technologies that are attracting attention and investment.

Energy Vault is a Swiss-based company specializing in gravity and kinetic energy-based energy storage. Their technology uses a multi-headed crane to store energy generated by renewable sources by stacking heavy blocks made of composite material into a tower, capturing potential energy from the elevation gain of the blocks. To produce electricity, the crane lowers the blocks to the ground, driving generators in the process. The company has just raised $100 million in funding from investors.

Malta, Inc. is an energy storage company based in Cambridge, Massachusetts that is developing an electro-thermal energy storage system. Energy generated from renewable (or other) sources drives a heat pump to create thermal energy producing both hot and cold reservoirs. The heat is then stored in molten salt while the cold is stored in a chilled liquid. To generate electricity, the temperature difference between the two reservoirs is used to drive a heat engine. Malta has recently raised $60 million in new funding including significant support from Chevron Energy Ventures.

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Energy Vault Raises $100 Million In Series C Funding

Chevron backs long-duration thermal energy storage developer Malta

Photo, posted October 16, 2019, courtesy of Jonathan Cutrer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Energy Vault

May 28, 2019 By EarthWise Leave a Comment

A potentially transformative utility-scale energy storage technology has won a 2019 “World Changing Idea” award from Fast Company magazine. Known as the Energy Vault, the technology seeks to be the successor to the granddaddy of grid energy storage: pumped hydro.

Shifting water between higher and lower reservoirs is still basis of the vast majority of global grid storage capacity. But it is limited both by its unique location needs and by environmental regulations.

A start-up company also called Energy Vault and based in both Switzerland and Southern California has come up with an extremely creative grid storage concept. The technology consists of a six-armed crane that stacks huge concrete blocks using a currently available source of cheap and abundant grid electricity, and then drops them down to generate electricity when needed.

The system is said to operate at about 90% efficiency and can deliver long-duration storage at half the prevailing price on the market today.

A full-scale Energy Vault plant, called an Evie, would look like a 35-story crane with six arms, surrounded by thousands of manmade concrete blocks, weighing nearly 40 tons each. When charging, the plant will stack the blocks around itself higher and higher in a Babel-like tower. To discharge, the cranes drop the blocks down, generating power from the speedy descent. This configuration can deliver 4 megawatts of power and store about 35 megawatt-hours of energy.

There isn’t even a factory needed. The company would deliver a crane from a manufacturer. The crane will then assemble the blocks onsite using recycled concrete. Operation is then fully automated. The system is expected to run for 30 or 40 years.

So far there is only a one-seventh scale demo unit in Switzerland. But this is a very intriguing idea.

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Energy Vault Wins World Changing Idea Award 2019 from Fast Company for Transformative Utility-Scale Energy Storage Technology

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio.