For centuries, humanity has erected towering structures to symbolize the grandeur of empires, leaders, religions, and corporations. Today, the trend of constructing tall buildings is more prevalent than ever. However, skyscrapers might soon be repurposed for a groundbreaking function renewable energy storage.
One major challenge with a power grid dominated by clean energy is the intermittency of renewable sources. Solar panels might not generate power during cloudy days, and wind turbines can be idle when the wind is calm. Conversely, there can be times when the sun and wind produce excess electricity.
Energy storage is crucial to balance energy generation with consumption. Various technologies, from advanced batteries to different storage methods, will likely be necessary to enhance capacity.
Enter the concept of battery skyscrapers. In late May, Skidmore, Owings & Merrill (SOM), the renowned architecture and engineering firm behind iconic skyscrapers, announced a partnership with Energy Vault, an energy storage company, to develop innovative gravity energy storage solutions.
Their design includes a skyscraper that uses an electric motor to lift massive blocks during periods of low energy demand. These blocks would store energy as potential energy. When energy demand increases, the blocks would be lowered, releasing the stored energy, which would then be converted back into electricity.
SOM’s expertise in skyscrapers is well-established. The firm designed New York’s One World Trade Center, Chicago’s Willis Tower (formerly the Sears Tower), and the world’s tallest skyscraper, Burj Khalifa in Dubai, standing at over 828 meters (2,700 feet).
Bill Baker, a consulting partner at SOM and structural engineer for the Burj Khalifa, highlighted this initiative as an opportunity to leverage their skyscraper expertise for energy storage, contributing to the reduction of fossil fuel dependency.
Achieving net zero emissions by 2050 will require substantial advancements in grid-scale storage, according to the International Energy Agency. Lithium-ion batteries, commonly used in electric vehicles, are limited in their ability to store energy for extended periods.
While lithium-ion batteries can handle short-term energy shifts, longer-term storage solutions like pumped storage hydropower are more effective. This method involves pumping water to a higher elevation during off-peak hours and releasing it through turbines during peak demand. However, it requires hilly terrain and ample space.
SOM and Energy Vault’s proposed superstructure could range from 300 to 1,000 meters (985 to 3,300 feet) in height, featuring hollowed-out elevator shaft-like structures for block movement, while still providing space for residential and commercial tenants. They are also exploring integrating pumped storage hydropower into these skyscrapers.
Such a structure could store multi-gigawatt-hours of energy, enough to power multiple buildings. However, some experts have raised concerns about the economics of skyscraper batteries, particularly regarding the space required for storage and the structural modifications needed.
Nonetheless, Energy Vault and SOM are optimistic about the commercial viability of their solutions. Energy Vault has already completed a 150-meter-tall (492 feet) project in China, the world’s first commercial-scale, non-pumped hydro gravitational energy storage system.
Supertall buildings could become part of the solution to offset their own carbon footprint. The construction sector is responsible for nearly 40% of global greenhouse gas emissions. Efforts to improve building sustainability include better insulation and the use of low-carbon materials like timber.
Innovative designs, like Stefano Boeri’s green towers in Milan and Dubai, are also making buildings more eco-friendly. However, with rapid urbanization driving taller constructions, the concept of gravity energy storage becomes more viable.
A very tall gravity energy storage structure could offset its embodied carbon within two to four years, according to Robert Piconi, CEO of Energy Vault.
“If you’re going high in a superstructure anyway, we’re just piggybacking on that,” said Piconi.”
SOM and Energy Vault are now seeking development partners to bring these visionary designs to life. Piconi believes that SOM’s reputation in skyscraper design will be instrumental in overcoming the challenges of building the first of these innovative structures.
