The Power of Thermal Storage for Affordable, Efficient Renovation
As cities grow hotter and electricity grids face increasing pressure from renewable variability, a technology once considered niche is gaining new attention: ice batteries. These systems, which store cooling energy by freezing water at night and releasing it during the day, are now being tested as a serious tool for both grid stability and building renovation.
We are currently exploring how ice batteries could be integrated into renovation projects. A pilot concept is in preparation, with the aim of demonstrating how “cooling-as-a-service” can complement energy performance contracting and bring direct financial value to building owners.
How Ice Batteries Work in Practice
The principle is simple. Water is frozen during off-peak hours, usually at night when electricity is cheap or renewable production is high. The stored ice is then used for cooling during peak demand periods. A single unit can typically shift 10–50 kilowatts of load for several hours, which on a hot afternoon means less stress for the grid and lower bills for the building.
In the United States, demand response programmes already reward building owners for such flexibility. For example, one project with “Ice Bear” systems showed consistent reductions of 30 kilowatts per building, allowing them to participate in utility programmes and earn additional payments. European cities are starting to take note, as more flexible consumption will be needed to handle growing shares of solar and wind power.
Why Investors and Building Owners Care
For building owners, the appeal is straightforward: less money spent on electricity. Where tariffs include demand charges or time-of-use pricing, every kilowatt of peak demand that can be avoided translates into measurable savings. Projects in California have reported simple payback times of 5–8 years by combining reduced bills with demand response revenues.
Beyond economics, there is resilience. Ice batteries provide backup cooling capacity when the grid is under stress or even during short outages. This can mean hours of continued comfort without relying on noisy and polluting diesel generators.
Integrating Ice Batteries into Renovation Projects
For us, the most interesting angle is how this technology could fit into deep renovation frameworks. By embedding ice storage in an Energy Performance Contract (EPC), we can guarantee measurable reductions in peak demand. Contracts can include clear performance clauses, and once savings are verified, these cash flows can be aggregated and refinanced—recycling capital into the next project.
Modularity is another strength. Ice tanks can be scaled according to a building’s size, from a single multifamily block to a network of buildings. This flexibility makes them a good match for renovation programs that are rolled out step by step.
Looking Ahead
In our region, the economic case will depend strongly on tariff design. Where demand charges are low, the payback is longer, while in markets with strong incentives for peak reduction the value is immediate. That is why part of our upcoming project will be to map out where ice batteries can make the most sense, and how they could be integrated alongside more traditional measures such as insulation and heating upgrades.
We believe ice batteries can become more than a “nice-to-have.” They could evolve into a standard part of renovation portfolios, creating measurable benefits for both building owners and the energy system.
Bottom note
We are preparing a pilot concept and looking for partners interested in testing ice batteries in real renovation projects. Could this approach be relevant for your city or your portfolio? Let’s explore the possibilities together.
