Mining shaft gravity storage startup completes fundraising as it prepares for demonstration – pv magazine International
Launched earlier this year, Wollongong-based startup Green Gravity is turning to Australia’s former cornerstone of wealth, coal mining, to ‘evaporate’ the last hurdle to an electricity system fully renewable. He proposes lifting and releasing ultra-heavy weights in legacy mine shafts, his reimagining of how the universal force of attraction, gravity, can be used to store renewable energy.
In all likelihood, this isn’t the first time you’ve heard of gravitational energy storage, but while hot Swiss startup Energy Vault has hit choppy waters recently, Green Gravity founder and CEO Mark Swinnerton , is adamant that his business has distinct merits, many of which stem from the fact that his concept is rooted in the redeployment of abandoned but very abundant infrastructure, reducing both the capital and environmental investment of projects.
Over the past few weeks, Green Gravity has completed its first official fundraising round from a range of private investors, securing $1.4 million “with a lot of excess interest,” it said. Swinnerton said. american magazine.
“We are working towards a bigger increase in a few months when we firm up the capital cost of the demonstration plant,” Swinnerton said, adding that he has committed with larger funds and has generated strong interest. (Energy Vault has attracted investment from Leonardo DiCaprio, among other big names.)
Green Gravity’s new staff, which includes Origin’s former Chief Transformation Officer Phil Moody, has also begun studies into the company’s supply chain and manufacturing footprint design. Something Swinnerton, who spent nearly two decades at mining giant BHP, insists will be much simpler than other storage solutions with minimal inputs and low processing levels.
“We don’t have to go and mine lithium or process it with new systems, we don’t have chemical recycling because we don’t have any chemicals,” Swinnerton said.
“People sometimes ask, ‘why are you suddenly able to find something so simple and yet it’s an open market?’ and my answer is, ‘it’s really because it’s never been necessary before.’
“The only reason it’s needed now is because renewable energy penetration has grown past an inflection point where all of a sudden natural coverage isn’t working in the market anymore, you need more of storage assets.”
The technological proposal
Green Gravity’s technology is flexible in two key ways, according to Swinnerton. “The first is that the power of the system is associated with the speed at which we move the weights through the mine shafts. Of course, a motor can run at different speeds, so we can choose to dynamically change the duration and values names of it, if necessary.”
“What’s unusual – most energy systems can’t change their duration dynamically,” Swinnerton said.
To do this, the company plans to use advanced software and artificial intelligence (AI).
“What we’re going to do is move several objects around without being able to see them. So AI is going to be able to help improve the responsiveness of sensing systems, so we can learn how to optimize movement, and better respond to the needs of the power grid in real time so we can learn how to match our system and support the grid.” , Swinnerton said.
“We’re looking at patterns that can potentially provide inertia, we’re looking at patterns that can definitely play into grid stability and the variety of frequency and voltage markets.”
“We are also designed to have multiple durations and we believe that these deep mineshafts [which can be double the height of the Sydney tower in depth] have a real opportunity for medium or long term storage.
Green Gravity is ultimately looking to market a range of storage products. The first, Swinnerton said, will offer between two and three hours of runtime, but he says there’s potential for a shorter runtime that focuses on network support as well as a long-running model.
Reuse reducing investment costs
The second area where Green Gravity can offer flexibility, Swinnerton says, comes down to the infrastructure it will use. “Because we can use the infrastructure that already exists, we can achieve a very low cost footprint.”
“We can attach capacity at unit costs similar to pumped hydro, but for much less capital.”
“So you don’t have to pay $700 million like you do in some of the big pumped projects. You just say, ‘well, we’ll pay $30 million.’ You’ll get less energy, but you’ll get a unit cost result similar to pumped hydro and there’s a lot of that.
That is to say, Green Gravity does not seek to do one big project, but rather many small projects – a model that reduces risk and offers greater financing flexibility.
“If you look, there really are sites everywhere”
Which brings us to another important aspect of the proposal: Australia is littered with mine shafts. “Australia’s mining history has been everywhere,” said Swinnerton.
The company discovered at least 3 GWh of potential storage capacity across the 175 sites it assessed and deemed suitable. “I can unequivocally guarantee you there’s more than that available – and that’s just in Australia.”
“There are many, many gigawatt hours up for grabs in the rest of the world that Australia should consider.”
Provide revenue streams for rehabilitation
Swinnerton believes the concept of Green Gravity will also offer legacy mine sites a valuable exchange, providing them with a revenue stream to fund their rehabilitation.
Again, this is a fairly simple concept: Green Gravity would step in and reuse site shafts and possibly other infrastructure, providing mines that no longer sell product with a steady stream of cash to restore sites. . This would be particularly useful for government-owned mine sites, where taxpayers have to foot the rehabilitation bill.
According to Swinnerton, this weekend’s “greenslide” election, coupled with the ongoing fight to secure battery materials, has only bolstered Green Gravity’s prospects. “I think there is a real chance for acceleration and I am certainly keen to engage with the new government on this,” he said.
The company is also in the final stages of establishing a major operating partnership, with an announcement expected in the coming weeks.
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