BIPV solutions for historic cities



The European Union-funded project brings building-integrated photovoltaic (BIPV) solutions to eight historic European cities. pv magazine recently spoke with Júlia Pereira, project coordinator at EDP New, about innovative solutions that integrate with the landscape in Évora, Portugal.

“The fact that we have focused on historic cities means that we have added challenges and legal obstacles to changing existing architecture,” said Júlia Pereira, project coordinator at EDP New. pv magazine. “All the solutions are designed so that the city’s aesthetics do not change, but still manage to rejuvenate the historic centers.”

Évora’s historic center is part of the UNESCO World Heritage List and therefore subject to special protection and preservation rules. Over the next few months, more than 40 BIPV solutions will be deployed in Évora, all designed to blend into existing buildings and structures.

These include the classic terracotta PV roof tiles from the Italian company Tegosolar. The Italian start-up in the solar electricity industry Dyaqua manufactures the so-called invisible solar solution by covering monocrystalline silicon cells with a surface that is opaque but transparent to the sun’s rays. About 3,350 PV roof tiles with a total output of 25.36 kW will be installed on the roof of Evora’s town hall. The power of each roof tile is 7.57 kW and the efficiency is 7.80%.

According to Pereira, purchasing PV roof tiles was not an easy task. Their production is still small-scale, which hinders profitability.

“The price per kW is 7,000 euros ($7,605),” he said. “It took six months to make the roof tiles and they are now ready for installation, which will take place between June and August this year.”

Photovoltaic glass made of amorphous silicon is integrated into skylights and windows

Photo: Câmara Municipal de Évora

Other solutions include amorphous silicon photovoltaic glass from Spanish BIPV specialist Onyx Solar. The colorful transparent solutions were the architects’ best choice for replacing skylights and windows in municipal buildings, markets and schools. For example, the roof window of Évora’s municipal market will have 74 units, each with a power of 236 W. Their efficiency varies from 2.8% to 5.76%. The installation covers 124.49 square meters and contains five glasses of different sizes.

The project will also introduce BIPV solutions that have not yet been commercialized. “We are developing economic models that can make these solutions viable for commercialization after this project,” Pereira added.

Residents of Évora’s historic center are said to be open to installing BIPV solutions, despite their lower efficiency and higher price than conventional rooftop electrical equipment.

“At the moment, we expect that these solutions can be a reality in the historic center, and in the near future the residents themselves will also have access to such a solution,” Nuno Bilo, mechanical engineer at Évora City Hall. told pv magazine. “The feedback we get from residents is that regardless of the efficiency of the tiles, they are interested in installing these BIPV solutions – better this than nothing.”

To facilitate citizen participation in the city’s historic center and beyond, the Pocityf project also includes peer-to-peer energy trading, collective self-consumption of municipal buildings, and a platform where individuals can register to sell or buy self-produced electricity.

The city hall is also preparing a tender for the granting of a business license for Évora’s communal solar power plant. The winner must develop renewable energy on public land and guarantee residents living in the historical center of Évora a lower kWh price than the spot market.

The Pocityf project started in October 2019 and is scheduled to end in June 2025.

Tegola amorphous silicon PV roof covering

Photo: Câmara Municipal de Évora

Onyx crystalline silicon PV glass BIPV solution

Photo: Câmara Municipal de Évora

David is a passionate writer and researcher who specializes in solar energy. He has a strong background in engineering and environmental science, which gives him a deep understanding of the science behind solar power and its benefits. David writes about the latest developments in solar technology and provides practical advice for homeowners and businesses who are interested in switching to solar.

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