Empa is one of the winners of the «Building Award 2025». A team from the «Concrete and Asphalt» department was honored for its carbon-storing concrete. The approach promises to significantly reduce emissions in the construction sector.
Empa was honored this year in the category «Research, Development, Start-ups» for its carbon-storing concrete mixed with carbon pellets. In front of more than 800 guests at the KKL Lucerne, the Empa team – Pietro Lura, Mateusz Wyrzykowski, Nikolajs Toropovs, Daniel Grossegger and Frank Winnefeld – accepted the «Building Award 2025». The independent jury, made up of experts from industry, planning, research, management and engineering, honored one winning project in each of six categories. The «Building Award» is presented every two years and honors outstanding engineering achievements in Swiss construction – inspired by the Oscar of the film world in several categories.
Concrete, the unexpected climate saver
Cement production is responsible for around 8% of global CO2 emissions. In order to reduce this proportion in future, Empa is researching the potential of CO2-neutral or even CO2-negative concrete. A team from the «Concrete and Asphalt» department has therefore developed a procedure by which biochar can be integrated into concrete in a practical manner. Although the first concrete products with biochar already exist, it is often added untreated. «The biochar is very porous and therefore absorbs not only a lot of water, but also expensive additives used in the production of concrete», says Empa researcher Mateusz Wyrzykowski. That is why the researchers rely on pellets: they are made of biochar, water and cement and replace some of the conventional aggregates in concrete.
The results so far are promising
The carbon pellets can be used to produce CO2-neutral or even CO2-negative concrete, which can be used like conventional concrete in buildings and infrastructure. «We are currently working with partners on the industrial production of our CO2-negative pellets. The first application in a building will take place in the new NEST unit «Beyond Zero» », says Pietro Lura, Head of Empa’s Concrete and Asphalt Division. The unit will be part of Empa’s NEST modular research and innovation building. It shows how promising CO2-reduced and CO2-negative innovations can be used in construction – and how buildings can even act as carbon sinks in the future. Concrete could store significant amounts of CO2 if conventional aggregates were replaced by biochar pellets.
The aim is a completely new global economic model
But a holistic approach goes beyond biochar as a carbon store. As part of the large-scale research initiative «Mining the Atmosphere», Empa is working on a concept whereby excess CO2 is taken directly from the atmosphere and used. The aim is to create a completely new global economic model and an appropriate industrial sector in which CO2 will serve as the raw material of the future.
The captured CO2 is first converted into basic chemicals such as methane or methanol. These can then be further processed to replace conventional building materials and petrochemicals. At the end of their life cycle, these carbon-rich materials are to be stored in special landfills to permanently sequester the carbon. Synthetically produced methane can also transport energy from sunny regions to countries facing seasonal energy shortages.
Implementation requires further progress
But, according to the Empa researchers, implementation requires further advances in materials research and process development, in particular to make optimal use of decentralized and fluctuating renewable energies. In addition, a focus on new business models, economic incentives, and appropriate regulatory frameworks is necessary to make a carbon-absorbing shareholder a reality.
