The concept is similar to that of Energy Vault and other start-ups, but Swinnerton believes using old mine shafts, rather than purpose-built high towers, will be its competitive advantage.
“They have to build a big building that’s hundreds of feet high and hang tens of thousands of tons from the top of the roof,” he says of competitors like Energy Vault.
“It’s going to take a pretty big set of steel beams with good geotechnical engineering and everything else to make it work.
“I don’t have to do anything, I can skip building a building and just use what was already there; a hole that someone else has already drilled and used and is now redundant.
Like Energy Vault, Green Gravity aims to increase weights when excess renewable energy is available; such as around noon when Australia’s vast fleet of photovoltaic cells pump electricity into the grid and make electricity consumption very cheap.
The weights would then be lowered at the precise moment when power is sought; either for industrial purposes, or simply because the prices on the electricity network make it an attractive time for dispatching.
As the weights are lowered, the rope holding the weights passes through a device called a “reel”, which then spins a motor.
In addition to producing clean energy exactly when it’s needed, Swinnerton’s concept could potentially provide accounting benefits for those who partner with Green Gravity.
Disused mine shafts tend to appear on the balance sheet of mining companies as liabilities, but by turning them into power generation centers, Green Gravity would potentially turn them into assets.
Swinnerton is close to securing its first two mine shafts for its first demonstration plants; one in New South Wales and one in Queensland.
Energy Vault has already secured collaboration and early-stage venture capital funding deals with BHP, the world’s largest oil company, Saudi Aramco and Korea Zinc.
Swinnerton won’t name names, but the rumor mill suggests partnership talks are underway with several of Australia’s biggest companies.
Green Gravity is Swinnerton’s first major play after leaving the business that got him started in the Port Kembla steelworks nearly a quarter of a century ago and helped fund his education academics in materials engineering.
The BHP Problem Solver
The next two decades were a process of constant reinvention as Swinnerton was tasked with solving some of BHP’s most intractable problems.
From Port Kembla he was posted to the Pilbara where he helped solve the logistical problems of the iron ore division by modifying the shape of ships’ hulls.
He held senior white collar roles in BHP’s marketing and economic analysis teams in Singapore, before returning to a senior blue collar role managing one of BHP’s coal mines in Queensland.
Like Clark Kent changing suits in a phone booth, Swinnerton quickly tackled the intricacies of industrial relations law, founding BHP’s innovative and controversial labor leasing company, ‘Operations Services’.
When asked how he managed to jump between the skill silos that trap most people’s careers in a particular discipline, Swinnerton said it was about solving problems.
“There’s a single point here about always taking on additional challenges,” he said.
“Use your discretion to start looking at issues that no one else has been able to address.
“Solving problems often ends up being a cross-disciplinary issue that gives rise to your ability to move on to a new discipline and move on to something different.”
It didn’t hurt that every time Swinnerton jumped into something new, he did it at one of the wealthiest companies in the world, which could surround him with the people and resources to thrive in new areas.
Now that he’s stolen the nest, how will he get away with it without the safety net that BHP’s deep pockets have put under all his previous jumps?
“I still have all of that around me – those are the people that I got to meet along the way,” he says.
“Given the relationships I’ve been fortunate enough to develop over the years, I still have access to some of the best thinkers and that has helped me refine my ideas.
“I haven’t found anyone who doesn’t want to spend time discussing issues, ideas and innovation, it’s been the most enjoyable thing since I left.”