The integration of on-again off-again energy sources like solar and wind is a pressing need for the Australian grid. According to Merrick Kerr, chief commercial officer at Energy Vault, the problem isn’t our access to renewables, but rather our ability to store energy long term.

“The energy storage industry is really still in its infancy,” says Kerr. “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.”

Harnessing natural forces

Energy Vault aims to address the need for long-term storage with its system that incorporates the concept of pumped hydro in a creative new way.

“The principle is very simple – when you want to store 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,” says Kerr.

“When you want the power back, you lower the bricks back to their low position, and the motor that was used to lift them now becomes a generator.”

Ahead of his presentation at the 2019 Australian Energy Storage (AES) Conference and Exhibition, Kerr explained that Energy Vault’s primary purpose is to provide a long-term, sustainable storage solution that cost-effectively boosts grid capacity.

“[Energy Vault] 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% renewable energy,” Kerr says.

“We have a levelised cost of storage 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.”

What goes up…

Two birds with one 35-tonne brick

In addition to its economic and sustainable storage methodology, Energy Vault’s other advantage lies in where it acquires materials for its bricks.

“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, and Australia obviously has a need to deal with these types of environmental issues,” Kerr says.

“In these circumstances we get a real win-win as you clean up an environmental problem and provide much needed energy storage.”

Hear more from Merrick Kerr about Energy Vault’s unique long-term storage technology at the 2019 Australian Energy Storage Conference and Exhibition, running from 13-14 June at the International Convention Centre in Sydney. To register, visit