Storing CO2 permanently in concrete

Most people agree that we need to take action to reduce global warming. While the majority soothe their conscience with individual important contributions such as separating recyclables, choosing an electric car, or reducing the heating temperature at home, Johannes and Valentin had a broader calling.

"Valentin and I realized, especially after the Paris Agreement, that solutions were urgently needed to remove CO2 from the atmosphere. It’s a scientific and political consensus that our net zero goals are not attainable if we, next to massively reducing our emissions, don’t also remove surplus CO2 from. We observed that few were focusing on the commercialization of carbon dioxide removal, and we wanted to develop an economically attractive that is both quickly scalable as well as high-quality.

Driven by an intrinsic motivator and the higher goal of solving a real and pressing global problem, they founded neustark. “Our ambition is to permanently remove 1 million tons of CO2 in 2030."

Destiny brought the co-founders together

At that time, Valentin was working at Climeworks, and Johannes dug his heels into the topic of permanent CO2 storage in mineral waste such as demolition concrete during his studies at the ETH Zurich. "Our paths crossed because we shared the same vision," says Johannes, and it sounds like destiny had given them a hint to team up. During the early phase, neustark focused on developing a carbon capture and storage technology for industrial-scale use. At that time, there was no established market for technical CO2 removal credits. Since 2019, the topic of and market for carbon removal has skyrocketed, also thanks to another Swiss pioneer, Climeworks.

In the mere five years since founding, neustark has gone from first idea to prototype to pilot to deploying first fully operational and commercial sites. In late 2022, the first site was launched; today, neustark has 20 plants in operation and more than 40 under construction. They have since established themselves as one of the globally leading carbon removal providers.

The Swiss carbon removal ecosystem has strongly developed in the last years, thanks to leading academic and research organizations in Switzerland as well as the start-up support given by public and private institutions for climate topics. 

"We collaborate closely on various levels with Climeworks and many other carbon removal companies, as we all share the same ambition: to scale the CDR industry at the hyper speed and scope needed to keep climate change in balance.," says Johannes.

Customers also served as development partners

Neustark’s technology repurposes concrete from demolished buildings and other mineral waste material as permanent storage for removed CO₂, using a process known as mineralization. Biogenic CO₂ is captured from partnering biogas plants, then liquified and transported to partnering construction waste recycling sites. There, as an add-on to the existing recycling process, the carbon dioxide is injected into demolition concrete granules. Neustark’s technology triggers an accelerated mineralization process, thus binding the CO2 permanently to the pores and surface of the granules. The carbonated granules can then be used by recyclers to build roads or to produce recycled concrete. 

Not only does this solution already remove thousands of tons of CO2 from the air and store it permanently, it also contributes to making the building industry more circular.

"We conducted our first material tests with carbonated concrete and found that the compressive strength increased, which is very attractive for our partnering concrete recyclers and producers. We collaborated with EMPA to understand why this happened, which significantly boosted us."

Tiefentaler explains that neustark's transition from research to business was very smooth. "We always had a good division of tasks and brought in people with complementary expertise, such as plant construction. We developed concepts with our customers, ensuring they were always close to the product. In the early phase, we sought customers who were curious to co-develop and engage in new ideas. The journey doesn't end with the first customer; it requires pioneers at various levels and for different prototypes."

"The journey doesn't end with the first customer; it requires pioneers at various levels and for different prototypes." – Johannes Tiefentaler - Co-Founder & Co-CEO neustark AG

"Our partners use the carbonated, recycling concrete granules to produce more sustainable building materials. More and more real estate developers – such as the city of Zurich and private builders – are looking to build with eco-friendlier material. The construction sector contributes heavily to CO2 emissions, so finding ways to decarbonize building is in the interest of everyone," says Johannes, referring to the construction sector's high CO2 emissions.

Building trust by demonstrating the solution 

Looking ahead, Neustark's focus is on further scaling. "Now that we have a proven solution, it's about rolling it out widely. We have sites in Switzerland, Germany, Liechtenstein and Austria in operation, and many other sites being built across Europe. Next year, we plan to enter the North American market. Our expansion strategy is based on clusters: We roll out our solution in areas with significant demolition concrete recycling already happening – so larger urban clusters –, by forming partnerships with biogas plants and concrete recyclers to build capture and storage sites.”

“To reach our goal of durably removing 1 million tons of CO2 in 2030, we will deploy around 1000 sites. Certainly an ambitious plan, but a doable one – and one certainly needed to help ensure a bright future of all generations on our planet."