The world's first solar folding roof, HORIZON, was built over the wastewater treatment plant of the city of Chur, Switzerland.

The solar folding roof increases the self-sufficiency of the ARA Chur

The project of the solar folding roof over the open clarification basin of the wastewater treatment plant in Chur is a worldwide innovation and shows an example of how the self-sufficiency of municipal infrastructure can be increased in an economical way. The solar folding roof produces approx. 550,000kWh of solar electricity on approx. 5’500m2 with an output of 643kWp per year, which corresponds to the consumption of 120 households.

Wastewater treatment can consume almost 100% of the solar power itself and thus relieves the load on the power grid. The solar power covers approx. 15%-35% of the annual requirement and increases the self-sufficiency to over 50%. This is in line with the trend, since wastewater treatment requires enormous amounts of electricity, and this can be largely produced with the solar folding roof over every wastewater treatment plant.

The current expansion of the Swiss wastewater treatment plants increases the total electricity consumption of all wastewater treatment plants in Switzerland by over 30%. With the solar folding roof, these wastewater treatment plants can cover this additional consumption themselves, locally and renewable, in a contemporary way.