A new storage technology involving a modified construction crane and an electric motor putting 35 tonne bricks on top of each other to build a tall, free-standing tower is providing long-duration storage. Ahead of his presentation at the Australian Energy Storage (AES) 2019 Conference and Exhibition, we caught up with Merrick Kerr, Chief Commercial Officer at Energy Vault, about his company’s unique approach to long-term power storage.
New long-term storage technology to use bricks
Merrick Kerr has long stood at the forefront of the energy industry’s evolution. In the early 2000s, he joined PPM Energy as its inaugural Chief Financial Officer and oversaw the company’s growth into the second largest wind developer in the U.S. Later, he served as CFO at eSolar, and Global CFO of the UK resource energy consulting firm Advisian, among other industry executive roles.
Now, as Energy Vault’s founding Chief Commercial Officer, Mr Kerr is eager to see what impact his company’s inventive new technology — which was recently chosen as the Energy segment winner on Fast Company’s 2019 World Changing Ideas list — can have on Australia’s blossoming storage sector.
“The energy storage industry is really still in its infancy,” Mr Kerr said. “If we are to achieve our global warming goals, we need a much higher percentage of renewables on the grid, and that by its very nature will require longer duration storage.”
Energy Vault aims to address this need with a methodology that is as simple as it is effective.
“The Energy Vault system takes the simple principles of Pumped Hydro but instead of using water, we use low cost 35 tonne bricks.
“The principle is very simple: when you want to store the energy, you simply use a modified construction crane and an electric motor to lift 35 tonne bricks from a low position to build a tall, free-standing tower. The energy is then stored as potential energy in the elevation gain of the bricks.
“When you want the power back, you simply lower the bricks back to their low position and the motor that was used to lift them now becomes a generator,” Mr Kerr said.
Disrupting the storage sector
Energy Vault’s primary purpose, Mr Kerr explained, is to provide a long-term storage solution that helps expand the capacity of the grid. This puts the company in a position to coexist with some storage technologies — and potentially replace others.
“[Energy Vault] is designed to provide long-duration storage; it was designed to allow a much greater quantum of intermittent renewable resources to be attached to a grid, and to provide the potential for off-grid, mini-grid and micro-grid solutions that can be run on 100 per cent renewable energy,” Mr Kerr said.
“Our technology can respond in milliseconds and ramps at over 33 per cent per second, so it can provide the ancillary services currently provided by chemical batteries.
“If you require long-duration and short-duration [storage], then you can dispense with the chemical batteries and just use our solution.
“We have a Levelised Cost Of Storage (LCOS) that in good sun areas allows us to combine with PV and deliver very close to 24 by seven by 365 solar energy for less than the cost of diesel generation.”
While seasonal energy storage — that is, the collection of thermal energy for later use, such as storing sun-heated water in summer until it can be used by heat pumps in winter — is one important industry objective that Energy Vault does not directly achieve on its own, Mr Kerr asserted that his company’s technology could be a vital and sustainable piece of the puzzle.
“What our technology does not solve is seasonal storage, and I feel that is where hydrogen can serve an important purpose.
“However, I do think our technology could play a major role in the production of green hydrogen, as hydrogen from natural gas is not carbon-free.”
Two birds with one 35 tonne brick
It is no secret that Australia has ample solar and wind resources, but as sustainable energy companies accelerate efforts to harness them, it has become increasingly apparent how unsuited the current grid is for intermittency.
The resulting need for a storage solution, combined with abundant supplies of industrial waste materials, help to make Australia an ideal candidate for a storage system like Energy Vaults.
“We believe our technology offers an excellent opportunity for Australia to accelerate its wind and solar program again, and this time without the negative impacts on the grid,” Mr Kerr said.
“In addition, we can make our bricks out of waste materials that would otherwise go to landfill, such as bottom ash from coal plants, mine tailings, contaminated soil etc., and Australia obviously has a need to deal with these types of environmental issues.
“In these circumstances we get a real win-win as you clean up an environmental problem and provide much needed energy storage.”