Final report – ZeroStrat: Strategies for new buildings with minimal emissions during construction (German only)

Switzerland’s building stock is responsible for around a third of domestic greenhouse gas emissions. More than half of building-related emissions can be attributed to the construction of buildings. For the Swiss Federal Office of Energy (SFOE), intep, in collaboration with ETH Zurich, investigated the potential for using construction products with low greenhouse gas emissions.

The “Nearly Zero Carbon Emission Strategies” aim to make energy-efficient buildings with low embodied emissions possible. The aim of the SFOE’s ZeroStrat research project was to analyze the potential of building products that emit as little greenhouse gas emissions as possible during production.

In three phases, the study investigated possible solutions for reducing embodied energy and greenhouse gas emissions in the construction of buildings. Innovative building materials and components as well as cross-material strategies were included (phase A), the possible reduction of embodied emissions for a test building was estimated (phase B) and an impact and acceptance analysis were carried out to record experiences, processes and requirements in the selection of building materials and components (phase C).

It was shown that a reduction of up to 40% in greenhouse gas emissions is possible with conventional concrete construction using innovative building materials and components, and a reduction of up to 45% with conventional timber construction. A reduction of 20% is possible when using conventional timber construction instead of conventional concrete construction. Renovation is preferable to new construction. Compared to conventional refurbishment, up to 33% of emissions can be saved by using straw, grass and hemp panels.

In terms of availability, at the time of the study (July 2023), the sustainable raw materials are not sufficiently available in Switzerland under the assumptions made. However, neighboring countries offer great potential for the import of straw and grass. Sourcing sustainable raw materials from neighboring countries results in fewer greenhouse gas emissions than using glass wool from Switzerland.

The stakeholder analysis revealed, among other things, that all stakeholder groups prioritize environmental friendliness, cost, durability, recyclability and reusability when selecting construction products. However, barely half of the participants rely on building or product labels when selecting construction products. In the interviews, these helpful tools were also associated with costs and effort.