Can ‘ice batteries’ cool down our soaring energy demands?

Researchers at Texas A&M University are perfecting a deceptively simple solution to our increasingly overburdened energy grid: ice-cooled buildings.

This approach, known as thermal energy storage or sometimes referred to colloquially as “ice batteries,” uses energy to freeze liquid overnight, when most people are asleep and electricity demand is lower. That stored ice is then melted to help cool building temperatures during peak hours. If successful, the end result is reduced electricity use for air conditioning during the day, which could decrease overall energy demand and help lower costs.

Creative solutions like these, presented in The Journal of Physical Chemistry, could play a more prominent role in the coming years, as the rise of AI data centers, which require constant cooling, continues to strain an already stressed energy grid.

Business are already using ice batteries

Ice batteries are already out of the lab and working in the real world. One of the most vivid examples is the iconic, Art Deco–inspired, 30-story Eleven Madison skyscraper in Manhattan. It reportedly uses 500,000 pounds of ice every day to cool the building during peak hours. That’s roughly the equivalent of three city buses packed full of ice cubes. Trane Technologies Commercial HVAC Americas, the company responsible for Eleven Madison’s cooling system, told CBS News earlier this year that their use of ice batteries reduces overall cooling costs by up to 40%.

“When everyone else is using their electricity in the middle of July to cool their building or to cool their homes, it’s a big draw on the grid,” Trane president Holly Paeper told CBS.  “This building won’t draw from that because it made its ice last night.” 

The ice-based thermal energy storage market has seen a significant uptick in interest in recent years. Trane alone (one of at least half a dozen companies operating in this space in the U.S.) claims it has made over 4,000 installations globally. Still, that represents only a tiny fraction of overall structures. The U.S. alone has an estimated six million commercial buildings.

Not all ice batteries are built the same 

But cooling all of that water also requires energy. That’s where the research conducted by the Texas A&M team comes in. Ice battery systems typically use salt hydrates as a kind of chemical binder to convert liquids into ice. During this conversion process, the salt hydrates interact with various other chemicals, called “nucleation particles,” to freeze liquids. The specific type of nucleation particles used, and the precise temperatures at which they interact, can significantly impact the overall reliability and efficiency of ice battery systems. 

This complex chemistry is what the researchers explored in their study. Getting the nucleation particles and salt hydrate composition right can reduce the amount of energy required to generate ice. Using less energy in that process translates to greater cost savings for building owners who install these systems. The chemical composition also affects whether ice batteries are compatible with specific types of HVAC systems or heat pumps. In this particular case, nucleation particles with the element barium were better at triggering a freeze.

“The ice battery technology has been around for a while,” Texas A&M Department of Materials Science and Engineering professor and paper co-author author Patrick Shamberger said in a statement. “But there are problems on the material side that I’m interested in: What’s the right material at the right temperature? Can we make it reversible? Can we make it last for 30 years?”

Related: [Could aquifers store renewable thermal energy?]

Ice batteries could help cool future AI data centers 

Data centers increasingly used to power advanced AI models require massive amounts of electricity. According to the International Energy Agency (IEA), data centers accounted for roughly 1.5% of global electricity consumption in 2024—a figure expected to triple by 2030 as countries race to build faster, more powerful AI systems. Much of that increased energy demand is being met by a familiar source: fossil fuels. Environmentalists warn that the growing reliance on natural gas to power AI infrastructure could cause countries like the U.S. to backtrack on climate commitments aimed at reducing carbon dioxide emissions.

The potential savings extend beyond data centers, too. Air conditioning accounts for about 20% of total energy use in homes and businesses, a figure which can spike to nearly 70% on especially hot summer days. Ice batteries certainly aren’t a silver bullet, but their widespread adoption could help stem the tide of this emerging energy dilemma. If scaled up, they could reduce overall energy consumption, which in turn would lessen the need to build new energy sources. Using ice batteries, in other words, could theoretically help offset the need for additional fossil fuel-based power.

“We don’t want to solve grid problems by building more power plants,” Shamberger said in a statement. “That’s a very costly solution and they’d have to charge higher rates overall.”

In a sense, ice batteries use modern chemistry to revive a process rooted in the past. As Nicola Twilley writes in her recently released book Frostbite, the modern concept of electric cooling we’re familiar with wasn’t truly invented until the 20th century. Before that, cooling, whether for a dining room party or to power a global supply chain of meat and produce, relied on the rapid transport of melting ice.

“As late as 1907, New York City, already a modern metropolis filled with automobiles and skyscrapers,” Twilley writes, “Relied on natural ice, harvested from lakes upstream and brought down the Hudson River on barges.”

Now, more than a century later, it’s looking like ice might be making a comeback.