As the global shift to renewable energy accelerates, the challenge of storing electricity from intermittent sources such as solar and wind becomes increasingly urgent. Power generation can plunge when the sun sets or the wind weakens, just as demand surges unpredictably, straining grids already adapting to an electrified future. Addressing this imbalance requires innovative energy storage solutions.
A New Force in Energy Storage: Gravity
One promising solution is gravity-based energy storage—a technology harnessing one of nature’s fundamental forces to provide a cleaner, more durable alternative to lithium-ion batteries. Now under trial worldwide, gravity batteries could offer a geopolitically flexible and environmentally sustainable means of large-scale energy storage.
The Need for Massive Energy Storage
Renewable energy sources can produce abundant electricity, but their inconsistency poses a challenge. Solar output drops to zero at night, and wind power is inherently unpredictable. Meanwhile, the electrification of transportation and the proliferation of AI-driven applications are driving electricity demand to unprecedented levels.
Traditional power grids struggle to reconcile these fluctuations, making large-scale energy storage critical. The current go-to solution—lithium-ion batteries—has its drawbacks. Lithium mining carries significant environmental and ethical concerns, battery performance degrades over time, and recycling remains a complex challenge. Furthermore, with China controlling approximately 72% of the global lithium-ion market, geopolitical dependencies have become a growing concern.
How Gravity Batteries Work
Gravity batteries function on a simple principle: lifting a heavy mass stores potential energy, and when that mass descends, the energy converts back into electricity via a generator. Unlike lithium-ion batteries, which lose efficiency over charge cycles, gravity-based storage does not degrade. As long as mechanical components remain intact, the stored energy remains accessible indefinitely.
Pumped hydroelectric storage—a predecessor to modern gravity batteries—has been used for over a century, pumping water uphill when energy is abundant and releasing it downhill through turbines during peak demand. While highly efficient, pumped hydro requires specific geographical conditions, including reservoirs and significant elevation changes. Gravity batteries, in contrast, can be built in a variety of locations using solid weights instead of water, expanding their applicability.
China’s EVx: A Monument to Gravity Storage
One of the most ambitious gravity battery projects is underway in Rudong, China. A collaboration between Swiss company Energy Vault and the Chinese government has produced the EVx system—an enormous mechanical tower designed to lift and lower massive blocks to store and release energy.
Standing over 120 meters tall, the EVx system has a peak output of 25 MW and a storage capacity of 100 MWh, with a projected round-trip efficiency exceeding 80%. Its anticipated 35-year lifespan makes it a compelling long-term solution. Notably, its building materials—soil, sand, and recycled waste—are locally sourced, reducing costs and supply chain vulnerabilities.
China’s aggressive expansion of gravity storage includes multiple EVx projects, with planned capacities ranging from 100 MWh to 660 MWh, and a proposed 2 GWh installation in Inner Mongolia. Collectively, these projects represent an investment exceeding $1 billion. Strategically, China’s pursuit of gravity storage presents an intriguing paradox: while the country dominates lithium-ion supply chains, it is simultaneously pioneering a competing technology that could allow other nations to diversify their energy storage strategies.
Innovations from Scotland: The Gravitricity Model
In Scotland, startup Gravitricity has taken a different approach. Instead of constructing towering structures, the company repurposes abandoned mine shafts to create gravity storage systems. By suspending enormous weights deep underground, the system can leverage the immense depth of mine shafts—sometimes extending three kilometers—to maximize energy storage capacity.
This method offers several advantages. It repurposes existing infrastructure, reducing capital costs while revitalizing post-industrial regions. Moreover, it eliminates the need for large above-ground structures, making it an appealing option for regions with decommissioned mines.
Challenges and Limitations
Despite their promise, gravity batteries are not a universal solution. Their efficiency diminishes at smaller scales, making them impractical for residential use. Engineering studies have shown that lifting even a 2,000 kg concrete block in a home would store the energy equivalent of just 12 AA batteries—far too little to justify the cost and complexity.
At grid scale, the primary challenge is the high initial investment. While gravity storage systems have lower long-term costs than lithium-ion batteries, securing upfront funding remains a hurdle. Additionally, mechanical components such as winches, pulleys, and cables require ongoing maintenance, though their upkeep is generally simpler than the recycling challenges posed by chemical batteries.
Another consideration is space. While gravity batteries do not require mountain reservoirs like pumped hydro, they still need significant vertical height or deep shafts. Urban areas may resist large tower constructions due to aesthetic or zoning concerns, while rural sites must balance feasibility with land-use regulations.
Beyond Lithium: The Changing Energy Landscape
Lithium-ion batteries will remain vital for many applications, particularly short-term energy balancing and portable electronics. However, supply chain risks, environmental impact, and safety concerns—including fire hazards—underscore the need for diversified storage solutions.
In the U.S., trade tensions with China and growing investments in renewable energy infrastructure are intensifying the search for alternatives. Gravity batteries, with their durability and reliance on abundant materials, could offer a viable path toward energy independence.
The Future of Energy Storage: A Multifaceted Approach
No single technology will dictate the future of energy storage. Instead, a combination of solutions—including gravity batteries, pumped hydro, lithium-ion, hydrogen fuel cells, and thermal storage—will work in concert to stabilize modern power grids.
Gravity batteries stand out for their longevity, scalability, and minimal reliance on scarce resources. Projects such as China’s EVx and Scotland’s Gravitricity demonstrate that the concept is not just theoretical but an emerging reality. If these systems continue to prove their efficiency and cost-effectiveness, they could become a cornerstone of large-scale energy storage, contributing to a cleaner, more resilient global power infrastructure.
As the world transitions away from fossil fuels, gravity-based storage may hold the key to ensuring renewable energy is not only generated efficiently but stored and distributed reliably—paving the way for a more sustainable future.
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