The architects behind the Burj Khalifa in Dubai — the world's tallest building, for those keeping score — are teaming up with a startup to turn future skyscrapers into massive, gravity-powered batteries.

Skidmore, Owings & Merrill (SOM), an engineering and architecture firm that's also worked on the One World Trade Center, is partnering with energy storage startup Energy Vault to build "gravity energy storage systems" that lift and lower massive blocks of recycled waste materials to provide electricity when it's needed the most.

It's a deceptively simple idea: during periods of excess renewable energy production, the facility's cranes can store large amounts of power — and then release it by lowering them back down and spinning up a generator, when demand is high and the energy supply is low.

"The combination of our pioneering work in gravity energy storage technology with the global track record and expertise of the most widely renowned engineering, design, and architecture firm in the world will provide the first platform toward delivering accelerated carbon payback in building construction and operation for the first time," said Energy Vauly CEO Robert Piconi in a statement.

Must Come Down

Energy Vault has already proven that its crane and waste blocks platform can be scaled up to store several gigawatt hours of energy. The company already has several existing projects in the works across the globe.

In March, the company completed a 100-megawatt-hour facility in China. A scaled-down pilot system near its headquarters in Switzerland can also store five megawatts of power.

It's an elegant solution to a very real problem: while sustainable energy production is on the rise, and some experts predict it could soon offset the need for future oil and gas projects, efficiently storing all that energy is a far more difficult nut to crack. Green energy generation may also not coincide with the time the energy is needed the most. For instance, solar energy peaks during the day, but demand may be the highest after the Sun goes down.

Apart from pulling up tons of material using cranes to store their potential energy, other gravity-based solutions include pumping water up from retired mine shafts in a process called pumped-storage hydropower, which can then be turned into electricity by having it pass back through turbines on the way down.

But despite having several projects underway, Energy Vault still has plenty to prove. Could the same idea really be scaled up to meet our ever-growing demands? While it's a clever engineering solution, the devil, as always, is in the details.