The construction sector is the climate villain that accounts for a large part of Sweden's emissions.
Stopping construction or renovation is not an option – but new smart solutions are emerging.
The construction of new homes north of Stockholm surprised and succeeded in halving emissions.
The construction and installation sector accounts for around 22 percent of Sweden's climate emissions. One of the major culprits is cement, which is used in concrete. It consumes large amounts of energy and water and is responsible for around 8 percent of the world's carbon dioxide emissions.
To completely stop building or renovating is not a solution, so we must try to find methods and materials that make it more climate-friendly, says Ida Karlsson, researcher at Chalmers in Gothenburg.
She has followed the construction of homes in Kista, northern Stockholm, in her research. The project had the explicit goal of achieving as low carbon dioxide emissions as possible without letting costs skyrocket.
36 percent lower
Now that the houses are ready for occupancy, calculations show that it has exceeded expectations. The construction has generated 36 percent less carbon dioxide emissions per square meter than similar projects. If you look at carbon dioxide emissions per person, they have been halved. Moreover, material costs were lower.
This is due, among other things, to the use of recycled steel, thinner inner walls, and thin and hollow beams, which required less concrete, says Ida Karlsson.
Another important factor is that the amount of cement has been kept down by using alternative binders, such as slag from the steel industry. In some inner walls, microsilica from grain ash has also been used as an additive that gives a lower climate footprint.
Although many efforts are being made to find new, more climate-friendly materials and methods, it has been difficult to scale up. The construction industry is, not least for safety reasons, surrounded by regulations and standards. Moreover, material costs have been low for many years.
In the construction industry, both material usage and time pressure have increased over a long period. It has not been deemed justified to spend extra time optimizing every part of a building to reduce material usage, says Ida Karlsson.
Tailor-made construction
Her lesson is that if construction projects are tailored, there is much to be gained.
Today, all walls and beams often meet the same tough standard. But not all parts of a building are exposed to weather and wind and do not require the same strength.
The fact that the parties involved had close dialogue about different choices was also crucial for success, she believes.
Tove Malmqvist Stigell is a docent at KTH in Stockholm and has long researched the environmental impact of the built environment. She believes that many are beating the drum for individual construction projects with climate initiatives. But to make a difference, processes and technologies must be scalable.
At the same time, it has been shown that it is possible to significantly reduce carbon dioxide emissions from today's levels, and that sends a message to builders, she says.
In recent years, there has been a strong focus on wood as the material that will make construction more sustainable. But according to Tove Malmqvist Stigell, the important thing is not a single material, but the overall climate impact.
It is possible to halve emissions even with cement and concrete. It becomes one-track-minded to only look at wood, she says.
Laws are required
At IVL Swedish Environmental Research Institute, Martin Erlandsson, adjunct professor of building materials at KTH, sits. He applauds positive examples, but according to him, more is required for the construction sector to quickly reduce its climate footprint.
Techniques and material alternatives exist, but now buyers need to order climate-improved for everything that is built, and then legislation is needed. It is often more complicated to find climate-friendly alternatives, and often a little more expensive.
In the construction and installation industry's roadmap Fossil-free Sweden, this – that pilot projects need to become standard – is pointed out as an important factor for the transition.
The industry is ready and often lies ahead of the regulations, says Martin Erlandsson.
The project was carried out by the client Bygg Vesta, the contractor AF-gruppen, and the structural supplier Concolis Strängbetong.
In total, 220 student and rental apartments with one to four rooms and kitchen are included. Construction started in 2022, and occupancy began in May this year.
The rent for a two-room apartment of 28 square meters is SEK 8,619 per month. A three-room apartment of 67 square meters costs around SEK 15,000 per month.
