One City’s Race To ‘Solarize Everything We Possibly Can’

One City’s Race To ‘Solarize Everything We Possibly Can’

Bordeaux’s submarine base was once a place of battle. Built by the Germans during the Second World War, the hulking concrete edifice in the north of the wine-loving French city was used to launch attacks against the Allied Forces. Today, however, the site is fighting a different kind of fight — the war on fossil fuels.

Its ammunition is 6,600 photovoltaic panels, which are being transported from the ground somewhat spectacularly by helicopter, reducing emissions five-fold compared to using cranes, according to city authorities. The outcome: A 13,000 square meter solar power plant, set to produce 3.4 megawatts of energy, which when completed in March 2026 will be the largest urban rooftop solar site in France.

“We have to solarize everything we possibly can,” says Claudine Bichet, the deputy mayor responsible for climate change and the energy transition at Bordeaux City Hall. “We believe in this approach and we are advancing very quickly.”

Since the election of Bordeaux’s ecologist mayor Pierre Hurmic in 2020, the ninth biggest city in France has undergone an electrifying transformation, underlining the growing potential and need for urban solar. In 2020, Bordeaux produced just three percent of its own energy. By the end of 2026, the proportion is set to reach 41 percent, largely thanks to solar but also through other renewables like wind and biomass.

That incredible transformation is in significant part thanks to the 60,000 square meters of solar panels that are being installed across the city on municipal buildings and in public spaces, from the roof of the iconic submarine base to schools, sports facilities, city hall, parking lots, cycle paths and even the city’s ring road.

It’s a shining example of harnessing sun-sourced energy and Bichet is unequivocal about the city’s goal: “We want to become France’s number one solar city.”

By the end of 2025, more than half of the targeted 60,000 square meters of solar will have been completed, according to Bichet, and she says the city is confident of reaching its ultimate goal by the end of next year.

One phase of the strategy focuses on what can go on the city’s rooftops. Bordeaux, which receives nearly 2,100 hours of sunshine per year, estimates that 354 of its municipal buildings are sufficiently exposed to the sun’s rays to produce significant amounts of solar energy.

Then there’s the transport infrastructure. Bordeaux aims to cover as much of its roads and cycle paths in solar as possible. As part of this, it has put out a call for proposals for the creation of a photovoltaic cover over two sections of the 275-kilometer ReVE cycle network, which should provide riders with shade in the summer and shelter from rain in the winter. Similarly, plans are underway to cover the city’s ring road with photovoltaic panels.

Ultimately, Bordeaux authorities see banking on solar energy as an affordable and accessible way of achieving its broader goals of shifting away from more polluting energy sources, like gas, towards electricity in the coming years, as well as cutting carbon emissions enough to achieve carbon neutrality by 2050. At the same time, the overall objective is to reduce energy consumption by 25 percent across all sectors and uses.

The approaches to achieving these shifts have been wide-ranging.

For one, it is now obligatory for solar to be used on the roofs of new or renovated buildings of a certain size. The city has also encouraged private and public stakeholders to work together, launching a program in June 2024 to facilitate this called The Alliance for Solar. Dozens of businesses, social housing providers, and public and private developers have signed up, including for a project at the Bordeaux Lac exhibition center.

Bordeaux has also opened an online portal for citizens to propose renewable energy “production acceleration zones” — in effect, allowing them to highlight abandoned roads, undeveloped parking lots or vacant lots where panels can be installed.

“We have to encourage everyone,” says Bichet. “We have had meetings, shared learnings. We want to have an open door.”

Yet one particular challenge for Bordeaux, home to a UNESCO-protected historic center that includes 347 listed buildings, has been finding a way to preserve its buildings while installing solar on them. In-depth studies have been carried out to analyze technical constraints, the weight of frames and, indeed, sun exposure.

“We engaged with UNESCO and with other cities, and we did big internal work [at city hall],” says Bichet. “Heritage must develop with the challenges.”

That has not always been a smooth process. For example, not all of the submarine base’s roof will be covered in panels in order to avoid it being visible from the ground – some claimed it would be a blight on the historic building, yet others, underlining the urgency of the climate crisis, said the entire space should be used. Nonetheless, the project, even with the imposed limitations, will avoid the emissions of 800 tons of CO2 per year (the equivalent of 400 round trips between Paris and New York) and businesses located within a one kilometer radius will be able to consume this electricity at a stable price, providing benefits to locals.

Maria Wall, a professor at Lund University’s Energy and Building Design department in Sweden, commends the “very impressive” developments in Bordeaux and in particular its success in managing to roll out solar while preserving its historic heritage.

In the past, many permits for construction were rejected due to preservation protections, but after obtaining a relaxation of UNESCO rules, that’s changed. In 2024, Bordeaux processed 261 requests for solar panel permits, more than seven times the number in 2020 (37). What’s more, 100 percent of those applications in 2024 received a favorable opinion, compared to 62.2 percent in 2020, reflecting a better institutional understanding of the process.

Technological advances such as the ability to produce transparent solar panels, or ones styled like building materials such as terracotta, have made urban solar integration easier than ever, according to Angèle Reinders, a professor of design of sustainable energy systems at the Eindhoven University of Technology in the Netherlands.

“These products already exist,” says Reinders, who co-authored a paper on building-integrated photovoltaics in May 2025. “In urban areas, it is already possible to make this integration seamlessly, reducing issues when it comes to building regulations and rules on use of property. If we are serious about the energy transition, then policy makers must help us overcome these permitting issues.”

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Reinders also says that developing urban solar faces other restrictions that don’t pose an issue in rural areas, such as limited space and access to land. “Bordeaux’s plan to focus on municipal buildings is great and effective, since they own them,” she explains. 

The future of urban solar in Bordeaux, therefore, is bright.

In France more broadly, solar appears to be the most appealing of all energy among the public. A survey published in May 2024 found that 87 percent of French people have “a positive opinion of solar energy,” compared with 67 percent for wind energy and 59 percent for nuclear power. And beginning in 2026, solar installations will be required on a significant number of buildings across the European Union, and public bodies will need to retroactively install solar on their buildings.

Solar energy also must be combined with other energy sources, adds Reinders, since the sun is not always shining. But she estimates that a city like Bordeaux could realistically source as much as 60 percent of its energy from the sun.

“Solar,” she says, “is such an abundant source of power.”