Civilization lies between a rock and a hard place. Our high standard of living comes at the cost of processes that emit carbon dioxide, and those emissions are rapidly pushing our planet out of the environmental envelope that allows us to live so comfortably. We desperately need a carbon dioxide removal (CDR) strategy.
The takeaway from my recent series on carbon capture and storage was that while the challenges of capturing emissions were great, the lack of transportation and storage infrastructure was the real problem.
One innovative Swiss company, neustark, has devised a clever solution for storing carbon dioxide captured from waste treatment facilities within one of the most widely used substances on earth—concrete. neustark aims to create a local, circular economy that transforms demolished concrete into a carbon-negative building material.
This may sound similar to Eco Material Technologies or other low-carbon cement producers which I’ve covered in this column. Eco Material and its competitors seek to reduce the carbon footprint of producing cement—the binder that holds concrete together. neustark, in contrast, capitalizes on concrete’s ability to absorb CO2 throughout its useful life, especially when it is crushed into smaller pieces.
neustark is a relatively new entrant in the CDR industry
neustark was founded in 2019 by Johannes Tiefenthaler and Valentin Gutknecht, two innovators determined to find a practical and scalable solution to the challenges of carbon sequestration. Tiefenthaler, a scientist with a doctorate from the world-famous university ETH Zurich, is an expert in mineralization—storing carbon dioxide in stone—the core technology behind neustark’s innovation.
Gutknecht, who previously worked in business development at Climeworks—a leader in direct air capture technology—brought his experience in marketing and scaling carbon dioxide removal businesses. Tiefenthaler and Gutknecht collaborated to create a network of local firms that remove carbon dioxide from the atmosphere, transform concrete into a tool for climate action, and help businesses reduce their carbon footprints.
Like many successful start-ups, neustark has identified a very specific problem to solve—CO2 emissions from waste management facilities, which capture methane generated in the decomposition of organic matter and sell it as renewable natural gas. Decomposition also generates carbon dioxide, which most facilities, lacking an economic solution for storing and transporting it—simply release into the atmosphere. neustark provides a pathway for that CO2 to be stored rather than released.
The heart of neustark’s process is an innovative reactor installed directly at concrete recycling plants. These facilities crush old concrete from demolished buildings to create aggregate, the pebbles and sand that cement binds together to form concrete. The neustark reactor infuses the crushed concrete with captured carbon dioxide from biofuel manufacturers and waste processing plants . The CO₂ reacts in a mineralization process with calcium ions in the concrete to form calcium carbonate (CaCO₃)—synthetic limestone. A single neustark reactor can draw down as much carbon dioxide in an hour as 50 pine trees can over an entire year.
Mineralization permanently traps CO2, ensuring it won’t return to the atmosphere. Even better, the resulting limestone aggregate is ready for use in construction, creating a closed-loop system for both concrete and carbon.
The carbon dioxide from one waste management facility is sufficient to supply ten concrete recyclers, and neustark focuses on building local networks to minimize the carbon footprint of the attendant CO2 liquefaction and tanker truck operation. The company presently has four emission source partners, with ten more in various stages of development. It has 40 locations in development on the sequestration side, and recently announced that it was expanding from Continental Europe with the inking of a deal with a new storage partner in the UK.
Because neustark sources its carbon dioxide from organic waste facilities, its solution is carbon negative—the organic waste contains atmospheric carbon dioxide that will never return to the atmosphere. This approach reminds me of Brilliant Planet, the company profiled in this column in the summer of 2024 that uses algae to pull down atmospheric CO2 and then buries the algae underground. neustark chemically “buries” the atmospheric carbon dioxide in roads, sidewalks, and buildings rather than in a borehole, but the idea is the same.
neustark generates revenues through equipment sales to the concrete recyclers to build the bolt-on mineralization reactors, and from the sale of high-quality carbon credits on the voluntary carbon markets. neustark handles the reporting and verification of these credits, sharing credit revenues with concrete recyclers. The company estimates its partners recoup the original equipment outlay over two to three years, after which the partner’s credit revenues fall directly to the bottom line.
In repurposing waste concrete and creating an economically viable pathway for CDR, neustark flips the narrative of concrete’s environmental reputation. As the demand for carbon credits and eco-friendly building solutions grows, neustark’s combination of science, engineering, and business innovation positions them as a key player in the fight against climate change. Intelligent investors take note.
