Fig.: Hugelshofer
One of the biggest challenges to reducing emissions lies in the hands of the cement industry. Holcim is now using a mobile solution to capture CO2 directly on-site, store it in concrete, and reuse it elsewhere as a high-quality building material. This, along with the use of electric trucks, also reduces the burden on transport routes.
At first glance, the fully automated storage system may seem unassuming – six fans and three differently sized containers, connected by pipes, stand at a recycling center in Oberdorf near Stans. But a look behind the scenes reveals something fascinating happening inside: CO2 from a wastewater treatment plant reacts chemically with recycled building materials and is permanently bound within them.
According to the company, the system can be transported anywhere in the country within just one day and installed at a new location or directly on the construction site. Project manager Georg Schmidt says about the recycled concrete granulate: "Thanks to this innovation, we can produce our resource-saving building material ECOPact Recarb anywhere in Switzerland and reduce logistics efforts to a minimum."
Photo: Holcim
The mobile plant can bind up to 500 tons of CO2 annually in the resource-efficient ECOPact Recarb system, which also improves its environmental footprint "as a side effect." This is roughly equivalent to the annual CO2 absorption of 25,000 Swiss fir trees.
In the production of cement, the binding agent in concrete, limestone is deacidified at high temperatures, releasing carbon dioxide. The technology of CO2 storage in concrete makes it possible to reverse this chemical process. Georg Schmidt, project manager at Holcim Switzerland, explains how the process works: “The evaporators convert the liquid CO2 stored in the tank into gas with minimal energy consumption. We then pump the gaseous CO2 into an airtight container where it reacts with the recycled aggregate.” This so-called reactor container is filled with recycled aggregates from regional demolition projects and forms the heart of the system.
Over the next two hours, the carbon dioxide reacts with the concrete granules in such a way that the CO2 on the surface of the demolition material is transformed into limestone – a process that would take years naturally. "This modern process allows us to carbonate up to 200 m³ of concrete granules per day," explains Schmidt. The processed demolition material is then used to produce the aforementioned ECOPact Recarb concrete. Because the CO2 is bound within it, it has a much better environmental footprint than conventional concrete.
Photo: Holcim
In 2021, Holcim added the first artificially carbonated recycled concrete to its product range, following extensive testing of the process in collaboration with the ETH Zurich spin-off "neustark". Less than two years later, the two companies developed a plant for this innovative technology.
A recent example of the use of this innovative concrete is the "Zephyr Ost" project, a production building for the household appliance manufacturer V-Zug. Holcim supplied 4,200 cubic meters of ECOPact Recarb for this four-story building. The use of carbonated recycled concrete resulted in a saving of 71 tons of CO2 compared to conventional construction methods.
Electric trucks are also an important step towards a more sustainable transport system. Since the end of January, in cooperation with the logistics provider Hugelshofer in Thurgau, a fully electric truck has been delivering cement to concrete plants in the Lake Constance region emission-free and quietly. "Two years ago, Holcim was one of the first building material manufacturers in Switzerland to put electric concrete mixer trucks on the road in the Basel, Geneva and northeastern Switzerland regions. We are pleased that we are now also relying on electrification in cement transport," says Michael Brogioli, Manager Logistics Operations Switzerland and Haut-Rhin at Holcim.
“An electric truck saves up to 80 tons of CO2 annually compared to a fossil fuel-powered diesel truck,” says Brogioli. Initially, an electric truck from the Volvo FH4x2 series will be used for customers in Eastern Switzerland, with the journeys being carried out by Hugelshofer Logistics. Further acquisitions are planned – with the goal of reducing CO2 emissions in Holcim's cement logistics by a quarter by 2030. The trucks are equipped with 540 kWh batteries and deliver 490 kW of power, which corresponds to a reliable range of 300 km. With a 350 kWh fast charger, the batteries are fully recharged in about 90 minutes. “With the investment in electric trucks and the corresponding charging infrastructure, we are taking a big step closer to our goal of sustainable freight transport,” says Hugelshofer CEO Martin Lörtscher.
Photo: Hugelshofer
The search for sustainable mobility solutions is also underway in the gravel sector: Holcim Switzerland is working intensively on converting vehicles and machinery to electric drive systems. Furthermore, expanding rail transport capacity is an integral part of the net-zero roadmap: railcars are used wherever possible. Currently, approximately 30% of cement deliveries are handled by rail, saving around 90% CO2 annually compared to road freight. With its electric truck operations, Holcim is focusing on those concrete plants in Switzerland without rail access.
At the international level, Holcim recently signed a letter of intent with Volvo for the acquisition of 1000 electric trucks by 2030.
