A new apartment complex called Papieri Cham that opened on the shores of Lake Zug in Cham, Switzerland, boasts carbon neutrality thanks to a combination of geothermal, hydro, and photovoltaic energy systems.

Instead of computing how much energy the complex would require, the builders, Cham Group, took the opposite approach and worked on achieving carbon neutrality by limiting the energy the complex could utilise. 


View from outside of the carbon neutral building in Switzerland. Image: Papieri Cham.

To counter the warming planet, countries have set ambitious goals of achieving net-zero emissions in the coming decades. Achieving these goals requires national-scale planning to counter emissions, but when individual units start working towards carbon neutrality, the target becomes more attainable. 

This seems to be the thinking behind building a carbon-neutral apartment complex from the very beginning. The buildings are made using timber-concrete composites or even recycled concrete where possible. 

The builders also ensured they used short transport routes to complete the construction while relying on Swiss building materials to keep the construction footprint minimal. 

Rendering of living units in the Papieri Cham. Image: Cham Group.

Pioneering work

Interestingly, the apartment complex’s location has a history of pioneering work. Back in the 1650s, when people in the area could not read or write, a paper mill was set up on the site, which then went on to become a major paper factory. 

The paper factory remained operational for 360 years before closing down in 2015. The remaining part of the location has been classified as historical buildings, while other sections were redeveloped to include apartments, lofts, studios, and workspaces. 

Georg Dubacher, the project’s energy consultant, explained that the project revolves around the concept of a 2,000-watt society. The system aims to reduce Switzerland’s per capita annual energy consumption from 8,000 watts to a quarter of this figure. 

The Papieri site has photovoltaic panel installations that provide up to 50% of its energy requirement. About 40% of the energy is provided by a hydropower plant that runs on the Lorze River nearby. 

The hydro power plant running near the site. Image: Cham Group.

The Cham group is also upgrading the hydropower plant to retire its old wooden turbine blades and replace them with more efficient ones. Fish and beaver ladders are also being built into the project so the animals can move up and down the river more freely.

The remaining energy requirement is being met through the grid, which also has its own carbon-negating measures in place. 

Rechargeable heating-cooling system

Even as the project aims to reduce its occupants’ energy consumption, it does not neglect their needs. Heating and cooling needs are energy-intensive and difficult to attain in a carbon-neutral setup. Still, the team achieved this using a rechargeable natural system. 

Interiors of the living spaces in the Papieri Cham. Image: Papieri Cham.

Using a geothermal energy system in which probes are buried more than 320m under the ground, the team was able to extract warmth from the soil to heat the building during the winter months, thereby cooling the soil under the building. 

In the summer, the system switches its role and begins extracting cold from the soil and giving it heat from the building, thereby recharging it for the colder months.

The Papieri Cham shows how each construction could be made carbon neutral in the future.