CleanTechnica Interview with Energy Vault CEO: PSH Energy Storage & Recycling Coal Ash

I was recently invited to interview Energy Vault President, Co-Founder and CEO Robert Piconi, who shared some of Energy Vault’s latest accomplishments and what sets it apart from competitors in the storage industry. ‘energy. Energy Vault’s mission is to accelerate the decarbonization of our planet by introducing the most advanced, environmentally friendly and cost-effective energy storage technologies. Robert explained how Energy Vault does this and highlighted these important points:

  • Energy Vault does not use lithium.
  • Energy Vault uses sustainable materials in its products.
  • Saudi Aramco has invested in Energy Vault.

The idea

Robert told me that Energy Vault was founded four years ago in collaboration with someone from Idealab (Bill Gross). “I’ve known Bill for about 15 years and he called me about this idea he had for energy storage.”

He explained that the idea has evolved from what it was at the start. Energy storage is a difficult problem to solve. He discussed the cost challenges of solar energy storage while noting that solar energy is now cheaper than ever. Energy Vault does not use lithium-ion batteries to store solar-generated electricity. Instead, it uses pumped-storage hydroelectricity (PSH).

“The cheapest storage, which historically was hydro, is between 15 and 20 cents per kilowatt hour. When you look at wind and solar—one to two cents and you have natural gas, which is five cents. You can see why people haven’t deployed renewables quickly because the cost of storing them is so high.

He explained that Bill called him with the idea of ​​taking pumped hydroelectricity – basically gravity – but instead of building big dams and damaging the ecosystem, the idea was to build a structure ( to take advantage of gravity, you need height) which would only use composite blocks designed with dirt. These organic composite blocks are the storage medium.

“We take the wind and solar surplus. It powers the engines, and when there is a surplus, it stacks these composite blocks high. This is all the potential energy in height – the weighted height is the potential energy. And then we have a software platform that automates this whole process.

“When the grid sends a signal that it needs power, the software kicks in and it lowers those composite blocks. It spins the motor and creates the electricity and just loads it onto the grid.

Robert explained that unlike lithium-ion batteries, PSH does not degrade over time. He added that Energy Vault solved the problem without using concrete, which makes it extremely inexpensive.

“For the first time, you can take low-cost wind and solar – one to two hundred – and couple that with large-scale low-cost energy storage. Since we’re not degrading with the time, that we can be built locally and that we don’t have scarce materials, it’s something that achieves a leveled cost – ultra-low – and therefore can be deployed at scale. created Energy Vault.

“What’s really important for us, the company, is that we stick to three parameters. For us, the first was the time and the urgency to bring it to market quickly. That’s why we didn’t focus on chemistry roadmaps or science over time – that would be uncertain. It also meant that we wanted to build something quickly. Which means, not something that would take years to build or have a supply chain.

“The second parameter that was important was the economy. I talked about going down to ultra low cost, so that meant some materials were banned.

“And then the third thing was environmental sustainability. So it’s unique for us. We use sustainable materials and avoid things like concrete. We also have a local supply chain, which minimizes greenhouse gases from the transportation sector. We build it locally, so it’s good for local economies and jobs.

“It becomes an interesting addition to lithium-ion, which focuses more on shorter durations such as electric vehicles and shorter duration energy storage. We become a very interesting and scalable addition to do a kind of duration higher, 2 to 4 hours, but increasing it to 6, 8, 10 and 12 hours in a transparent, economical way, with very high efficiency.

Composite blocks

The composite blocks that are the medium used are mostly made of earth but can also contain materials such as coal ash, which usually ends up in landfills. Robert explained that the blocks have environmentally sustainable solutions that use waste. Other types of waste include retired wind turbine blades and tailings from the mining industry.

The photo below is a screenshot of Energy Vault’s investor presentation. You can see the composite blocks and details on how waste such as unrecycled coal ash can be recycled and used to store solar and wind energy.

Screenshot of Energy Vaults Investor Presentation

The composite blocks used in the trials were made of 96% earth which was innovated with a Cemex polymer developed that would allow earth and water to be mixed with cement powder. This allows Energy Vault to avoid the use of concrete.

1/4 scale model

Robert explained that they built a 1/4 scale model and tested it. Then they went up the ladder. SoftBank backed the company with an investment which it used to build a 5MW system, shown in the video above. It’s the first generation and Energy Vault and its customers have tested it.

This culminated in Energy Vault’s signed deals with Saudi Aramco — announced last spring. Enel Green Power is another company that has partnered with Energy Vault to incorporate decommissioned wind turbine blades into Energy Vault’s gravitational energy storage technology.

Circular economy

Using decommissioned coal and wind turbine waste in the floor product is an integral part of Energy Vault’s circular economy. Robert explained the different types of coal ash and noted that coal-fired power plants generate millions of tons of coal combustion residues (CCR). Energy Vault’s product is a solution to this, helping to convert waste into energy.

Saudi Arabia

Energy Vault Pumped Storage Hydropower

Image courtesy of Energy Vault

One thing Robert wanted to highlight is the importance of investments and partnerships with Saudi Aramco and Enel. The former is the largest energy company in the world and the latter is the largest Independent Power Producer (IPP) in the world. Getting them on board with Energy Vault’s circular economy plan is exciting, Robert told me.

Regarding Saudi Aramco, a fossil fuel company, supporting Energy Vault, Robert said:

“I’m really excited about their support for our storage. And the fact that they invested in our company, what does that mean? This means they are strategically behind Aramco and their needs to make the clean energy transition. It’s a massive signal from what has been a traditional OPEC leader and a company whose people clearly expect to help not just transition, but lead.

“I think that’s a great signal and the fact that they’re going to be moving to alternative fuels like using the sun to make green hydrogen, for example, is perfectly clean fuel. So I think that’s a great signal and we’re very happy to have their support, because some of our larger initial deployments will be in the Middle East.

Images courtesy of Energy Vault


Do you appreciate the originality of CleanTechnica? Consider becoming a CleanTechnica Member, Supporter, Technician or Ambassador – or Patreon Patron.




Have a tip for CleanTechnica, want to advertise or suggest a guest for our CleanTech Talk podcast? Contact us here.