Concrete is one of the technologies that enable the renewable energy transition—but wait, there’s more!
For centuries, concrete has been one of civilization’s indispensable building materials, supporting bridges, buildings, dams, highways, ports, power plants, and much, much more. Its role has always been structural. A new generation of energy infrastructure now suggests that concrete may soon add an entirely different purpose. It will not simply support the electrical grid; it may become part of the grid itself.
In Rudong, China, global energy storage company Energy Vault has commissioned one of the world’s first commercial concrete energy storage systems. Instead of storing electricity chemically, as lithium-ion batteries do, the facility stores energy mechanically. When electricity from nearby wind farms and solar arrays exceeds demand, electric motors lift thousands of massive concrete composite blocks into a tall storage structure. When demand rises, gravity lowers those blocks and converts their potential energy back into electricity. The facility is rated at 25 megawatts (MW) with 100 megawatt-hours (MWh) of storage, achieves better than 80-percent round-trip efficiency, and is designed for an operating life of approximately 35 years with minimal storage degradation.
Cost data for the Rudong facility has not been independently verified, but estimates place the project at around $90 million. In comparison, a lithium-ion phosphate battery (LiFePO) capacitor would cost $30 million to $35 million. At first glance, lithium-ion appears to be the winner. However, the batteries require cooling and gradually lose storage capacity, eventually needing replacement at least once for a 35-year operating life. That will cost around $20 million before inflation. Concrete lasts much longer, and gravity never sleeps.
While material quantities have not been formally published, engineering estimates suggest the project contains between 35,000 and 70,000 cubic meters of concrete. That is a substantial amount of material. The more important observation is that concrete can transition from just supporting infrastructure to being a key component in the energy ecosystem.
The real story (as always) is the economics
Across much of the world, wind farms and solar facilities routinely generate electricity when demand is low. During these periods, wholesale electricity prices often collapse and may even become negative because production exceeds consumption. Grid operators are forced to curtail renewable generation, meaning perfectly good clean electricity is discarded because there is no economical way to store it.
The economics of Rudong are driven by the facility’s role as a reliable capacitor. Every megawatt-hour captured during periods of oversupply represents renewable energy that can be stored and sold at a higher price when higher demand returns—a strategy known as energy arbitrage.
Wholesale electricity markets are based on supply and demand. Low supply brings high prices, and high supply brings low prices. The resulting price gap can be up to $100 per MWh. Assuming one complete charge-discharge cycle each day (an overoptimistic assumption), a 100-MWh gravity storage facility could deliver approximately 1.28 terawatt-hours of electricity over its 35-year design life. At that price differential, the gross value created through energy arbitrage approaches $128 million. If we cut this in half to account for real-world inefficiencies, it still will likely outperform the lithium-ion option.
Why should our industry care?
Here is where the story starts to matter for the concrete industry. Based on the available estimates, each cubic yard installed will deliver between 14 to 28 MWh of dispatchable electricity over the facility’s lifetime, with a midpoint near 19 MWh per cubic yard.
That suggests our industry may eventually need a completely new way to measure value. Consider a new engineering metric: Concrete Energy Productivity, which we’ll shorten to CEP. (Yep, I made this up out of whole cloth!) The metric would measure the lifetime megawatt-hours of dispatchable electrical energy enabled per cubic yard of installed concrete under defined operating conditions.
The idea is admittedly speculative, but so was embodied carbon reporting only a few years ago. Someday, CEP could be discussed alongside compressive strength, durability, permeability, shrinkage, service life and cost. We could then measure infrastructure by what it supports AND what it enables.
‘Charging’ forward
Gravity has been storing energy since the beginning of time. Now, we have combined modern automation, advanced power electronics, and engineered concrete into a commercially viable system that transforms otherwise wasted renewable electricity into dispatchable power.
Will gravity storage become commonplace? Probably, but not everywhere. It is unlikely to totally replace lithium-ion batteries, just as ready mixed concrete never replaced structural steel. Instead, it will likely find its greatest opportunities where renewable generation is abundant, transmission capacity is constrained, electricity prices fluctuate dramatically, and wind or solar farms are routinely forced to curtail production. These conditions torment renewable energy providers across the globe.
For more than a century, our industry has optimized the cost and performance of concrete structures. The next century may challenge us to optimize something even more valuable: the lifetime contribution those structures make to society. As we roll that movie forward, concrete will no longer be viewed simply as the foundation of the energy transition. It will likely become one of the technologies that enable the transition.
Article originally published in Concrete Products August 2026.
