Closing loops in the concrete industry: Holcim and neustark present a new solution for the permanent storage of CO₂ in residual water

• Holcim Central Europe West and neustark are jointly commissioning 14 plants for the removal of CO₂ in Switzerland, Germany, Italy, and France.
• As part of their strategic partnership, Holcim and neustark are launching a new CO₂ removal technology that represents a further step towards promoting the circular economy.
• A new solution for permanent carbon removal has been developed and rolled out in which CO₂ is captured at point sources, such as biogas plants, and stored in mixed water.

Holcim, one of the leading providers of innovative and sustainable construction solutions, and neustark, a pioneer in CO₂ storage in mineral waste streams, are putting 14 newly developed storage facilities for slurry water into operation. The two Swiss companies are thus jointly taking up the challenge of using more sustainable practices in concrete production to meet the climate targets that have been set.

Last year, the Holcim Group and neustark entered into a partnership, setting new standards for a more circular concrete economy. As part of this strategic cooperation, Holcim Switzerland will now be the first company to use the storage facilities in large numbers.

The solution was tested at the Avenches concrete plant in 2023 and impressed with its autonomous functionality and the low additional workload for plant personnel. "We are proud that a plant in Switzerland has been selected as a pioneer site to test this innovative technology," says Rafael Chocomeli, Freiburg/Neuenburg Market Manager at Holcim Kies & Beton AG. "The benefit-cost ratio of this process is excellent and ideally complements the existing CO₂ process storage in the demolition material to improve the footprint of the building material further".

Following the pilot project’s success, the solution is now being used at several Holcim locations throughout Switzerland. Additional facilities are planned for Germany, Italy, and France. This new and innovative technology for the permanent storage of CO₂ in residual water, produced in the cleaning process for concrete production equipment, is a significant step towards achieving Holcim's sustainability goals and neustark's mission. By 2030, Holcim has set itself the goal of reducing its net CO₂ emissions per cubic meter of concrete in Switzerland by almost 40%. For neustark, the solution is a significant step in its mission to permanently store one million tons of CO₂ in mineral waste streams by 2030.

Depending on the site, the plants can permanently store between 40 and 200 metric tons of CO₂ annually. "Our CO₂ reduction path for the concrete product portfolio envisages a massive reduction in the CO₂ footprint by 2030. The new technology, developed and implemented with neustark, is another lever for advancing decarbonization," says Tobias Sugg, Head RMX Performance. Neustark also emphasizes the importance of the partnership: "With the rollout of our technology for CO₂ storage in residual water, we are establishing a new material flow for our technology and setting new standards for sustainability in the concrete industry. Working with Holcim, we continuously remove metric tons of CO₂ from the atmosphere and store them permanently. This cooperation shows how innovative technologies and joint efforts can lead to sustainable solutions that promote the circular economy and contribute significantly to achieving climate targets," says Valentin Gutknecht, co-founder and co-CEO of neustark.

This is how the mixed water CO₂ storage facility works:

The mixed water from the residual water basin is fed to the facility by a pump and then brought into contact with biogenic CO₂ in a static mixer. The CO₂ reacts with the cement phases in the water and turns into limestone, which is thus permanently stored. This process also neutralizes the highly alkaline water. After enrichment, the mixed water can be reused for concrete production.

The CO₂ comes from nearby biogas plants and is produced during biomethane production. The permanent storage of this biogenic CO₂ creates negative emissions.

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Media contacts

Holcim Switzerland: Fabiana Gamma, fabiana.gamma@holcim.com, +41 79 433 83 37

Neustark: Elmar Vatter, media@neustark.com, +41 79 267 11 10

About Holcim (Schweiz) AG

Holcim (Schweiz) AG is one of Switzerland's leading providers of innovative and sustainable construction solutions for building construction, civil engineering, and infrastructure. The company produces concrete, gravel, and cement at 55 sites throughout Switzerland and recycles demolition materials into resource-saving products. Sustainability is at the heart of our business activities: As a pioneer in the development of sustainable solutions, Holcim Switzerland has set itself the goal of producing climate-neutral and fully recyclable building materials by 2050. To achieve this vision, Holcim is focusing on the circular economy and reducing CO₂ along the entire value chain. Holcim Switzerland is a subsidiary of the globally active Holcim Ltd. and employs around 1,500 people in three cement plants, 16 gravel plants, 36 concrete plants, and several recycling centers.