Ice (both solid and melting) may soon help pave the way to a carbon-free world, offering an alternative to energy-gobbling air conditioning and a new way to store excess renewable energy.
“The cooling properties of ice don’t need to be explained. But did you know that ice can store energy and help companies reduce their carbon footprint in the process?” asks the World Economic Forum (WEF).
Though the first assertion (of basic physics) hardly needs defenders, the second is central to the premise behind the “IceBrick” technology under development by Israeli start-up Nostromo Energy.
In hot countries today, air conditioning drives “a huge portion of the peak demand in the energy grid,” the WEF says. That demand that has already doubled since 2000, and it’s set to increase sharply over the next three decades—not just in places that face very hot weather, like certain regions of China or India, but also in more temperate zones.
Standard air conditioning systems use a lot of energy because inputs are required at every stage in the process: from the cooling coils that remove heat and humidity from the indoor air, to the fan that disperses the chilled air, to the mechanisms that release the collected heat to the outdoors.
Enter Nostromo’s IceBrick, which “promises to cut the environmental and financial cost of air conditioning for large commercial buildings” in a two-step process. The first is the conversion of water to ice “using electricity at times of low demand, for example at nighttime, or when there is a surplus of electricity from renewable sources such as solar and wind farms.” The second step is energy discharged by “melting the ice and pumping the cold water through the building until temperatures drop in the evening.”
The system “not only relieves the electricity grid from the intense energy demands of air conditioning and lowers electricity costs for building owners,” the WEF explains. “It also offers a storage solution for excess renewable energy that would otherwise go unused.”
That secondary capacity could prove a particular boon. “Storing surplus renewable energy is critical for balancing out the intermittent nature of renewables and one of the biggest challenges on the road to reaching net-zero emissions and halting climate change,” the WEF says. That makes thermal energy storage (TES) systems like IceBrick a critical supplement to the battery storage systems already in place and being developed to store renewable power.
Nostromo’s innovation is not the first form of TES technology. In a report from 2018, Inside Climate News describes how towers of molten salt are already helping solar farms meet the challenge of providing electricity on demand.