From Lyon’s futuristic riverside district to Évora’s UNESCO-protected historic centre, cities are rewriting the rules of urban energy. Facing radically different constraints, both are experimenting with ways to cut emissions and produce more energy than they consume. Their message for Europe? The challenge is real and creativity is essential - but there is no excuse for not moving towards decarbonisation


Impossible to miss, with its ultra-modern glass structure and futuristic forms designed by Austrian architect Wolf D. Prix and his firm Coop Himmelb(l)au. Measuring 90 metres in width and 180 metres in length, the Musée des Confluences is the calling card with which the French city of Lyon greets anyone arriving by motorway from the south of the country. As its name suggests, the museum is also the emblem of an entire district which today mirrors the same sense of modernity, but which, until only a few years ago, was instead synonymous with decay and abandonment. “La Confluence is located at the confluence of the two rivers that cross Lyon, the Rhône and the Saône. It is an area spanning 150 hectares which, despite being in the city centre, for a long time was paradoxically somewhat disconnected from the rest of the city, either physically or in people’s minds. In the 18^th century there were just marshlands, and later the area was long used to host facilities that the city did not want within its urban fabric. There were two prisons, a freight port, a gas factory, an international wholesale market with a large complex of warehouses supplying Lyon’s markets and supermarkets, and so on,” explains Étienne Vignali.

Vignali is Project Manager at SPL Lyon Confluence, a private company with public shareholders such as the City of Lyon and the Lyon Metropolitan Authority, which led the redevelopment of the Lyon Confluence district. “There was a major image shift to achieve, because the district’s reputation was extremely degraded. At the same time, Confluence proved to be a valuable testing ground for innovations that had not yet found concrete application at local scale,” he adds. It was in this context that, in 2015, the first ‘îlot mixte’ was built here: Europe’s first positive-energy, mixed-use buildings block combining housing, offices and retail spaces.

This milestone reflects an environmental ambition that has been present since the very beginning of the district’s redevelopment project, with a strong commitment to building performance, aimed at ensuring that buildings consume less energy while also being more comfortable to live in. “Quite early on, there were also numerous actions focusing on renewable-energy production, first at the scale of these ‘îlots’, and later at the scale of the entire district,” Vignali notes.

Driving this transformation was the determination to give Confluence back to the city and to bring Lyon’s residents back to Confluence. What made this possible, he explains, was also a very specific context: “It is extremely rare to have so much available land in a city-centre district, with such high redevelopment potential. The two local authorities, the City of Lyon and the Lyon Metropolitan Authority, therefore decided to make a significant effort to capitalise on the strong interest in real-estate development—an interest that might not have existed had the district been more peripheral.”
More than 1,500 kilometres away, the challenge of decarbonisation and renewable-energy deployment faced by the Portuguese city of Évora, appears almost diametrically opposite on paper.

“Imagine a city surrounded by ancient walls, with several access gates and buildings mostly painted white, just as they were when first constructed. Walking through the streets of the centre immediately gives you the impression of stepping back in time. In front of the beautiful city hall, all you need to do is look up to feel transported back several centuries and realise that the past is still there, right before your eyes,” says Humberto Queiroz.

Project Manager at the EDP R&D Center, Queiroz is also responsible for implementing in Évora the solutions developed within POCITYF, a European project supporting historic cities in becoming greener and smarter while respecting their cultural heritage. “Évora’s city centre is protected as a UNESCO World Heritage Site. This means, for example, that you cannot install conventional photovoltaic panels or carry out other interventions that elsewhere would allow citizens to produce their own electricity. We are therefore working on the installation of energy-management solutions that help residents optimise their consumption, and in some selected buildings we are testing building-integrated photovoltaics (BIPV), a type of PV technology that blends into the architecture and remains visually unobtrusive,” he adds.

If in Évora the invisibility of the tested solutions is essential to preserving the city’s touristic value and historic landscape, Lyon offers another example that confirms how innovation and sustainability can also enhance territorial attractiveness: Zadiga Cité. Built in the 1960s as a technical garage made of concrete pillars and beams, this modern building—now home to an architecture studio, two communication agencies and “a space for collective reflection on environmental and urban challenges”—is the first positive-energy building in the Confluence district.

“It is a 1,300 m² ground-floor building with generous ceiling height and several mezzanines. We gave it a distinctly contemporary, factory-inspired character, with abundant natural light and large open spaces that create strong visual connections with the surroundings and allow sunlight penetrate deep into the interior”, explains architect Thierry Roche, who, together with his partners, as he puts it, ‘turned a toad into a princess’. “When we first visited the site, the building was a burnt-out shell, surrounded by demolition sites, prostitution and drug trafficking. The challenge was to transform a space marked by desolation into an emblematic place and to become pioneers of the renewal of the Confluence area.”

Building on previous experience with positive-energy buildings such as the École des Ponts ParisTech in Champs-sur-Marne, Atelier Thierry Roche focused on insulation and airtightness using bio-based materials, solar shading, photovoltaic production—with 600 m² of solar panels—as well as natural ventilation and free cooling. “The building produces about 2.4 times more energy than it consumes. Energy demand in summer is very low thanks to the absence of air conditioning. We also installed a highly efficient heat pump and a ‘tempering’ system, which reinjects water at 23°C into the ground to provide occasional cooling of the air, without operating as conventional air conditioning,” Roche explains.

The creation of Zadiga Cité is part of the broader redevelopment of Confluence and represents the first stone of what professionals refer to as the project’s ‘third phase’. “The idea was for the building to act as an architectural and urban catalyst, serving as a starting point for other modules dedicated to innovation in sustainable construction,” Roche explains, before pointing to a bet that the city seems to have won also in terms of visibility: “There is a great deal of communication around these kinds of projects that they also act as territorial marketing for the city. The investment is therefore largely offset by the fact that this is a demonstrator site that attracts significant attention.”

This ambitious modernisation effort has also been enabled by Lyon’s participation in several EU–funded projects, such as Scalable Cities - whose final event the city hosted in August - and ASCEND, coordinated by Étienne Vignali himself. “European projects primarily allow us to test new solutions to improve environmental performance of new and renovated buildings, increase the local production of renewable energies, expanding green spaces and decarbonized mobility solutions, and evaluate and improve the actual performance of our projects. When you do something for the first time, you make mistakes, it takes longer, and therefore it costs more. But there are other aspects that are just as important as funding, if not more, such as the possibility to collaborate with publics and private stakeholders from different countries, and to get inputs from cities, research institutes, industrial partners, and other external experts, for targeted topics, in a specified period,” says Vignali.

The exchange of practices, experiences and know-how is also one of the core pillars of Évora’s contribution to POCITYF, where it serves as one of the main testbeds alongside the Dutch city of Alkmaar. “Within this project, our goal is to act as a frontrunner and test solutions that can later be replicated in other cities facing restrictions on PV installations due to architectural and heritage constraints. There are many such cities across Europe, and helping them overcome these obstacles would significantly increase renewable-energy production and enable many citizens to take ownership of their energy,” Queiroz says.

One key lesson learned, he adds, is that when dealing with protected buildings, time must be allowed for proper planning. “Cities wishing to adopt these kinds of solutions must first and foremost be determined and ready to face a whole series of challenges. But there is no excuse for not moving towards decarbonisation. The technology exists. The knowledge is being built. And with a little creativity, it can be done,” he concludes.


Article by Diego Giuliani


Images Confluence: credits to © SPL Lyon Confluence / Studio Fly - Timelapse Go - Aurélie Pétrel - Laurence Danière - Thierry Bazin
Images Évora: credits to H2020 POCITYF Project
Images Zadiga Cité: credits to Vladimir de Mollerat du Jeu - Pierre-Aymeric DilliesPhotos
Full gallery and HQ photos here


Contacts:
Project coordinator:
João Cravinho – EDP
joao.cravinho@edp.pt

Communication Secretariat:
info@pocityf.eu

Project website: https://pocityf.eu
LinkedIn: https://www.linkedin.com/company/pocityf/
YouTube: https://www.youtube.com/channel/UCfINly2sme7pxYOm8n2Z1Dw?view_as=subscriber