An unusual aspect of Tahar Diab's large yellow house with a pond in Rognac, near Marseille, is the view from above. The tiled roof is covered with 16 strategically placed solar panels to track the sun throughout the day. The panels produce so much energy that he earns about €1,000 a year by selling them to the energy company EDF. It is necessary to use electricity from the grid only when there is no solar energy - especially at night.
Diab spent 17,000 euros to install the panels. The figures are very high, also because the houses are very big: the average cost of installing a house in France is about 10,000 euros, excluding batteries. But Diab believes that his panel will be profitable in seven years. "This green sun," he marveled, "is much cheaper than fuel." Currently, energy prices are very expensive." It's no wonder, he says, that you see "more information boards" around Ragnats.
In France, only 600,000 homes are equipped with solar panels, which is less than 2% of the country's housing stock. However, the market is growing rapidly. The explosion helps answer two questions currently being asked far beyond France: Which house is best suited for solar power? And what's the fastest way to get more?
First, a caveat: solar panels are not a perfect solution to climate change. Their production emits CO₂, although emissions over the lifetime of the modules are much lower than fossil fuel production. Although recycling facilities are available, most panels need to be replaced after about 25 years. More than 80 percent of global solar panel production is done in China, in part with the help of Uyghur Muslim forced labor. However, solar energy is one of our best ways to reduce emissions.
Since 2020, residential solar power has faced two blows: first, due to the accident, more people have time to sit at home and think about electricity, and second, the energy crisis caused by the Russian intervention in Ukraine. Jérôme Moutard, co-founder of Diab panel supplier DualSun, says France's residential solar panel market will double between 2021 and 2022. "The market is not big," he added sarcastically, "so a doubling is possible."
Very high energy costs force homeowners to generate their own electricity. Centrally regulated electricity prices in France rose 15 percent in February and another 10 percent on August 1. Higher prices shorten the time it takes for people to pay off the costs of a solar installation. Moutherd said the average time to profitability in the sunny south of France is 7 years, and 10 years in the darker north. According to his calculations, the average annual return on investment for 25 years was 12 percent.
In addition, the installation of panels increases the value of the property, because the next owner will have their own power generation system. Depending on the model, DualSun warrants its modules for 25 to 30 years. They can last significantly longer, after which 95-100 percent of the components can be recycled.
A good place to see the large-scale use of solar energy is in Lyon, 400 km south of Paris. I visited on an ordinary hot summer day in a new climate: 30 ° C and blazing sun. The Métropole de Lyon local government wants to increase the use of solar energy in its territory tenfold by 2030.
The focal point of Lyon is La Cfluence, the area between the confluence of the Saone and Rhône rivers in the center of the city. It was once a grimy industrial area, but over the past two decades, houses, offices and shops have replaced dilapidated factories, warehouses, railway stations and prisons. Today, La Confluence calls itself a "green area" that invites you to visit; Wealthy workers go hiking and cycling and eat on restaurant terraces.
The push for solar energy began here about 15 years ago. State-owned Lyon Confluence now hopes to install the panels on every eligible building in the neighborhood. One afternoon, Maxim Valentin, director of a sustainable development company, took me to the roof of the Marken train station. The building, which used to be a wholesale market, is now a cultural center. But it is more than that: Marche station has become a source of energy.
The roof is covered with slanted black photovoltaic solar panels that produce more energy than the building consumes. Enough left to move Confluence's corporate headquarters across the street. (Photovoltaic panels convert sunlight into electricity, while thermal solar panels convert water, space heaters, etc.
The roof we're standing on offers some visual lessons on what makes a building suitable for solar panels. First of all, the roof is huge. "The bigger the area, the more profitable it is, the more energy you save," Valentin explains. Second, the roof is flat and practically bare, so it's easy to install the panels. Third, the building is still being restored: the cost of installing the panels, about €50,000, is only a fraction of the total cost of the renovation. After all, the Marche train station is not in the shadow of one of the neighboring buildings and therefore receives a lot of sun.
Not every roof at La Confluence is suitable for solar, but the goal is to use each one for something. Valentin pointed to the low roof in the shadow of the Marche train station. Since it was too dark for solar panels, grass was planted instead. Then he pointed to the old high roof in front of us, complete with chimneys and television aerials. It's also not solar-powered, but on sunny days its occupants could theoretically draw power from solar panels on a nearby building. During times without sun, they will fall back on other energy sources in France's electricity grid.
"The idea," Valentine says, "is to create an energy community so that solar can benefit local residents." If a rooftop system produces one kilowatt of electricity, that kilowatt can be consumed by neighboring households. In the case of Lyon fusion, he admitted that the idea of direct energy transfer was "fictional". Almost all of the solar energy produced here goes to the national grid. It is unclear where the electrons generated by the roof of the Marche station go. But the idea of "car consumption" makes residents who have to sign a formal solar contract feel like they benefit from the panels. At this point, many people seem to be unaware that they are getting energy from the sun.
If you stand on the roof of the Marché train station, you can see the black edges of the solar panels on some of the surrounding buildings. There are more than 40 solar plants in the neighborhood, said Bruno Gaiddon of Hespul, a renewable energy specialist that advises Lyon Confluence. He added: "This environment is a kind of laboratory for what will be produced in France in the future." And not just in France: Lyon is one of eight European cities participating in the EU's ASCEND project to find solutions for the energy transition.
What works in La Confluence can work in similar conditions even in colder climates. The key to solar energy is light, not the sun. Even after dark, the Marché station produces less solar energy than the moon, street lights and light pollution. In fact, several Nordic countries lead sunny France in terms of solar production. Germany has the most solar homes in Europe at around 1.8 million, but even Poland, Belgium and the Netherlands have more absolute numbers than France, according to research and consulting firm LCP Delta.
By definition, to cover the more than 98 percent of French homes that do not have solar power, the panels would have to be installed in old buildings that are completely unsuitable. The city of Dijon, 200 km north of Lyon, is trying to do just that. École Buffon Dijon has become France's first "positive energy" school, supplying 14 public buildings with solar panels. Panels have also been installed in some of the city's old council buildings.
Dijon's learning curve is very steep. Sara Bello, director of urban and residential regeneration for the local government of Dijon, said that ultimately the decision was made not to place the panels directly on the roof of the residential building. The top of the elevator shaft and ventilation devices are obstructed and shaded. Instead, the panels are placed on rails around the roof. He said, “If I tell you it's easy, no, it's not. However, we learned a lot from our rookie mistakes."
With any solar project, he says, you need to know what type of roof you're dealing with. They are said to have worn the panels for decades. The wiring of the building must be strong enough to allow the sun to enter the grid. Project managers must learn to deal with bureaucracy. But there is progress. Now, Bello says, "we're hearing the first questions from homeowners about solar panels."
A potentially game-changing French regulation took effect last year: Renewable energy must meet or exceed the energy needs of every new home. This should boost the use of solar power, LCP Delta predicts. Ask a French expert to speed up your next search and suggestions will abound. Gaydon proposes streamlining the government's administrative procedures for installing panels on homes, charging VAT and issuing interest-free loans to help cover installation costs.
DualSun's Mouterde said what France needs most is more qualified panel installers. "It's a more limiting factor than the number of roofs." He notes that in France you can train to become a certified plumber or electrician, but not a certified solar installer. DualSun plans to set up its own academy to train installers.
Surya has great potential. "We're just getting started in the housing market," Mutherd said. Clear a few hurdles, and in a decade the blackboards in Diab's home and downtown Lyon could be widespread across the continent.
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