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Redefining solar technology with RETRACTABLE SOLAR POWER FOLDING ROOFS. Unlocking photovoltaics for waste water treatment plants towards self-sufficient plants.

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Solar folding roof helps power water treatment

As the demand for urban space becomes ever greater, an EU-funded initiative has developed a novel approach for harvesting solar energy. This disruptive technology produces solar power where needed most while easing planning pressure on competing activities.

Climate Change and Environment icon Climate Change and Environment
Energy icon Energy

At present, most photovoltaic systems are placed on the roofs of buildings. However, there is great potential, still rarely used, for placing them over open areas used for municipal and commercial activities, such as wastewater treatment plants (WTPs) and vehicle parking. The HORIZON project addressed this challenge with a retractable folding roof that integrates non-glass solar cells for harnessing solar energy. The roof unfolds when the sun shines and automatically retracts into a storage unit to protect it from storms, hail and snow. “This is made possible thanks to the innovative, lightweight construction and the patented cable-based folding mechanism we have developed,” notes Gian Andri Diem, co-founder and managing partner of SME dhp technology AG. Thanks to a grant from the Industrial Leadership - SME Instrument, dhp technology has been able to prove HORIZON system’s potential for the European market. “Without it, we would have had to fund the feasibility study with our equity or cash flow. The Horizon 2020 label has opened many doors, enabling us to tap into a network we didn’t have access to before,” explains Diem.

More efficient use of space

The technology enables unrestricted movement beneath the 5 m high roof, as supporting columns can be placed up to 20 m apart. This allows the dual use of space on already exploited areas without restricting their main function. The two main applications of the folding solar roof are to-date parking-logistics areas and WTPs. WTPs are one of the most expensive public utilities in terms of energy requirements, accounting for more than 1 % of electricity consumption in Europe. Although most of the EU objectives concerning water protection have been achieved, most of these ageing plants show unsustainable energy consumption and must be optimised to the maximum and renovated accordingly. Andreas Hügli, co-founder and managing partner, notes: “For a project to be economical, we need an area of at least 1 000 m2. We started with WTPs because we saw great potential there worldwide. With the solar folding roof, WTPs can switch to energy-efficient operation and produce part of the energy they need locally.”

Twice the benefits

In these times of increasing electrification of transport, the potential of the HORIZON system can now be recognised. “Our company is targeting operators of large parking spaces and logistics areas. The solar folding roof comes with the charging infrastructure and turns every asphalt surface into a charging station for private and commercial vehicles, as well as providing shade,” Hügli adds. By targeting the WTP sector, HORIZON will substantially contribute to the achievement of the EU’s energy strategy and the 2050 climate targets. This will increase the ecological integration of supply infrastructure across Europe. Municipalities and states can show the private sector how energy-intensive infrastructures can be ‘used twice’ to partially supply themselves with solar power. HORIZON technology has been designed with the future in mind as it can be integrated into current and future trends, such as IoT, smart mobility and smart grids. “Our technology provides a solution to the increasing densification of our living spaces and eases the competition amongst industry, housing, cropland, recreational spaces, and energy production,” Hügli concludes.


HORIZON, WTP, solar folding roof, solar energy, logistics area, charging station, vehicle parking, photovoltaic, wastewater treatment plant

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