Stacked in 20-foot shipping containers at a Norwegian fertilizer works, specially engineered concrete charged to 390°C is replacing the gas boilers that once kept production running through the night
The containers look exactly like the ones stacked on a cargo ship.
Each is a standard 20-foot steel box, the same size that moves refrigerators and grain around the planet.
But inside each one, several hundred metric tons of engineered concrete sit threaded with steel pipes, charged to temperatures that would soften aluminum, holding enough heat to power a factory through the dark hours.
Unlike an electrochemical battery, this system charges directly with heat, making it suitable for industrial applications that lithium ion cells simply cannot serve.
The remarkable part is not the container.
So what is the concrete actually doing inside it, and how does it switch off a gas boiler?
Why ordinary concrete was almost the answer all along
Concrete holds heat the way a cast iron pan does: slowly, steadily, and for a long time. That thermal stubbornness, the same property that makes a concrete floor cold on a winter morning, turns out to be useful when you need to store industrial heat and release it hours later on demand. The physics was never a secret.
What took time was making the material reliable enough to cycle between cold and hot thousands of times without cracking. Standard construction concrete cannot do that. Thermal cycling at high temperatures opens micro fractures in ordinary mix designs, and the pore structure changes in ways that degrade performance over years.
The engineering challenge was to reformulate the material from the ground up: higher thermal conductivity, greater chemical stability at temperatures approaching 390°C, and resistance to mechanical stress across decades of daily use. The result is a purpose built concrete embedded with a network of steel tubes through which a heat transfer fluid circulates. When surplus heat is available, the fluid runs hot and the concrete absorbs it; when the factory needs steam, the flow reverses. Unlike an electrochemical battery, this system charges directly with heat, making it suitable for industrial applications that lithium ion cells simply cannot serve.
A fertilizer plant in Norway became the first real test
The logical place to try this was somewhere that already ran on enormous quantities of industrial heat and had a clear incentive to cut gas consumption. The first commercial project went into operation in 2022 at a fertilizer manufacturer’s facility in Porsgrunn on the southern Norwegian coast, a site that has processed nitrogen fertilizer for over a century.
Each module holds roughly 2 MWh of thermal energy in a standard 20-foot container footprint, and multiple modules can be combined to reach any required system capacity, from a few MWh up to GWh scale. That modularity matters in a heavy industrial setting where space is constrained and civil works are expensive.
The core material, a high temperature concrete called HEATCRETE, delivers strong thermal capacity and conductivity alongside resistance under thermal stress. Standard container handling equipment can position each unit without specialist cranes or civil works beyond a concrete pad. The Norwegian Minister of Energy visited the installation after commissioning, a signal of how seriously the country’s industrial sector is watching the results.
The numbers behind a concrete battery
Thermal energy is stored at temperatures up to around 390°C, well above the boiling point of water and hot enough to generate the steam that chemical plants depend on. The modules are designed for a service life of more than 25 years, which matters commercially: a lithium ion battery in grid service typically requires significant cell replacement within ten to fifteen years, adding cost and waste that concrete systems avoid entirely.
The system shows near zero performance degradation and is made of fully recyclable materials, primarily steel and concrete. That combination of abundance and durability stands in sharp contrast to an energy storage industry that has spent two decades debating lithium supply chains and cobalt sourcing. The company behind the technology has raised $131 million in funding as industrial operators across Europe weigh how to decarbonize process heat, which accounts for roughly a fifth of total global energy use.
The catch that keeps this from being a simple story
The system does not generate electricity on its own. It stores and releases heat, which means its value depends entirely on whether a given factory already needs steam or high temperature process heat as its primary energy input. A data center or a wind farm cannot use this directly.
Charging the concrete still requires a heat source. In Porsgrunn, that source is the industrial process itself combined with renewable electricity converted to heat. But in facilities that lack a surplus heat stream, the economics depend on electricity prices, and that equation looks different in a country with cheap hydropower than in one relying on gas fired generation. Even so, a second installation followed in February 2023 for a Belgian label and packaging manufacturer, extending the proof beyond Norway into a market with a different grid mix.
What a fertilizer works in Norway says about the future of industrial heat
The Porsgrunn installation answers a question that has dogged industrial decarbonization for years: whether heat storage at factory scale could be built from materials already lying in every construction yard on earth. The answer, it turns out, is yes.
Much as ordinary rust turned out to underpin the first iron air battery connected to a national grid, the cheapest available structural material held a serious answer to an expensive industrial problem. No exotic supply chain required, and no exotic mineral at risk of a price spike or a geopolitical embargo.
What remains open is how far that answer travels. Process heat covers an enormous range, from food drying at 80°C to glass manufacture above 1,000°C, and no single storage medium covers the whole spectrum. The concrete battery works well across the band that fertilizer, chemicals, paper and packaging occupy, but the upper end of heavy industry still needs something different. Advances like the geothermal well that put the UK’s first ground-heat electricity onto the national grid hint at how thermal energy in unexpected forms keeps finding its way back into the power system. For now, a row of grey steel boxes on a Norwegian waterfront runs through the night, keeping a chemical plant warm without a gas flame, on nothing but the memory of heat stored in concrete.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
