There are nearly 11 million light points in France, the equivalent of one lamppost for six inhabitants, according to the latest figures from the French Environment and Energy Management Agency (Ademe). It is up to the municipalities to decide to turn off public lighting at night and some have decided to take the plunge recently, thanks to the confinements linked to the Covid-19 pandemic..
However, it is proving very difficult to map this dynamic on a national scale. Quite simply because the data is almost non-existent. “We are currently working on a public lighting standard, where each municipality can, if it wishes, inform of its number of light points, the lamps used…” explains Jspoil Amsallem, research engineer at the National Research Institute for Agriculture, Food and the Environment (Inrae).
Nevertheless, two consulting firms expert in the analysis of satellite images, TeleScop and DarkSkyLab, have modeled data in the middle of the night in the Occitanie region since 2014. In the image above, the bluer the area, the weaker the public lighting. However, this method has biases and the results cannot accurately represent light pollution. In the details of the data communicated by the region, 520 municipalities out of 4,516 practice extinguishing after midnight in Occitania, i.e. more than one municipality in ten. Franceinfo explains to you why – economic, environmental, even touristic – certain cities have made this choice.
Because they make significant savings
Public lighting weighs heavily in the energy expenditure of municipalities. According to its last five-year report for 2019, Ademe assesses this competence at 41% of the electricity expenditure of municipalities. The bill has increased with the rise in energy prices. The opening up to competition endorsed by the Nome law (for “New organization of the electricity market”), applied since 2011, is also singled out.
“The Nome law increased the bill by 25%, and faced with this increase, some municipalities found themselves stuck.”
Roger Couillet, vice-president of the French Lighting Associationat franceinfo
Some mayors are targeting a reduction in the overall operating grant, paid by the State to communities. This envelope fell by 11.5 billion euros in 2014, according to the annual report on the financial situation and the management of local authorities, forcing some cities to reduce their consumption. “We had to save money somewhere, so we cut our 7,800 light points the following year”remembers Dominique Fouchier, mayor of Tournefeuille (Haute-Garonne).
In addition, between 2005 and 2017, the cost of energy dedicated to public lighting doubled, from 7.7 to 15 euro cents per kilowatt hour, according to the latest report from Ademe. Faced with this situation, municipalities are trying to reduce their annual bill by turning off their streetlights. “Since this decision in 2015, the municipality has saved nearly 163,727 euros per year”figure Martine Berry-Sevennes, assistant delegate for the ecological transition of Colomiers (Haute-Garonne).
Despite this gain, some municipalities, like Fleury (Aude), are reconsidering this decision. “Residents believed there was a breakdown and did not understand the device. So we turned the lights back on in 2019”, testifies David Bouyer, director of city services. Loss due to this back-pedalling: 15,000 euros per year. To compensate for this shortfall, the municipality has decided to change its lighting park with LED lamps, which consume less energy.
Because they reduce their energy waste
Today, the majority of facilities still need to be renovated. The potential for reducing consumption is estimated between 50 and 75% in municipalities with less than 2,000 inhabitants, according to Ademe (PDF link). Sebastien Vauclair, founder of the design office DarkSkyLab, warns : “We can save energy and public expenditure, while polluting more. We must therefore keep light sobriety in mind. That is to say, really reduce the impact of light pollution on the environment with, in particular, more orange lamps.” The energy issue has become increasingly political. Evidenced by the growing number of elected officials in charge of energy in French municipalities.
In 2017, sodium lamps, which consume more energy, accounted for 57% of the French lighting stock, according to Ademe’s latest five-year report. At equivalent consumption, an LED luminaire illuminates 20% to 40% more than a sodium lamp. Communal light parks are increasingly moving towards LEDs. Thanks to them, it is possible to reduce light intensity during the night, and therefore light pollution. Sodium lamps are destined to disappear in Toulouse in order to reduce the energy cost of public lighting. “By 2026, our entire lighting fleet will be made up of LEDs”projects Jean-Baptiste de Scorraille, deputy mayor in charge of public lighting.
For a large number of elected officials, the interest is twofold : save money and pollute less, by transforming aging light parks. And for good reason, 40% of the luminaires in service are over 25 years old and require an overhaul, according to Ademe (PDF link). “The old streetlights were not designed to light up. Today, they get dirty and the light no longer comes out of the light fixture, so it pollutes and consumes for nothing”, explains Bruno Lafitte, engineer at Ademe, specialist in issues related to lighting. He adds : “Luckily they are on the verge of extinction!” Indeed, these old luminaires are among the most polluting, because their luminous flux is oriented towards the sky and not towards the ground. However, a 2018 decree on light pollution provides for the removal of these balls from public and private spaces in 2025.
Although France that is rather a good student in the fight against light pollution because of its legislation on the subject, the Court of Auditors considers, in a report of March 18, 2021, that this municipal competence is exercised in a manner “too dispersed and without a long-term vision”. In response, the Minister for the Ecological Transition, Barbara Pompili, announced the “lum’ACTE” program on February 16. Endowed with 10 million euros, it will allow “diagnose, within two years, 3 to 4 million light points and renovate at least 70%”. The Minister recalled that reducing energy consumption is the “first of the three pillars of the energy transition”, during the last committee on sustainable development and regional planning.
Because light harms nocturnal biodiversity
“Light pollution is part of a genocide on biodiversity”, says Sébastien Vauclair, from the DarkSkyLab design office. Increasingly, public policies take animal welfare into account. Because if the light nuisance can disrupt the circadian rhythm of the human being, it also hinders the night life of other living beings. Many insects, for example, are attracted to light, and night lighting prevents their movements from progressing smoothly.
Artificial light from street lighting can affect all aspects of animal life, such as foraging.
“Luminous halos prevent good bird migration”, adds Jennifer Amsallem, of Inrae. On the map above, we can see that switching off the streetlights in certain towns reduces these halos in the middle of the night. This creates nocturnal corridors allowing migratory birds, which find their way around thanks to the stars, to move more easily.
To preserve biodiversity, “we must rekindle the stars”, confirms Agnès Langevine, vice-president in charge of climate, the green pact and sustainable habitat for the Occitanie region. This is what the city of Toulouse is doing to protect animal life around the Garonne. “We turn off the lights near monuments at 1 a.m. to let the nightlife unfold”explains Jean-Baptiste de Scorraille, deputy mayor in charge of public lighting.
“The advantage of this pollution is that it is completely reversible”, enthuses all the same Bruno Lafitte, of Ademe. Switching off lights at night thus has immediate effects on nocturnal biodiversity.
Because their starry sky becomes a tourist asset
“We are not a village with a nightlife”, recognizes Daniel Bancel, mayor of Sauliac-sur-Célé (Lot). This village of 134 inhabitants has considerably reduced its lighting at night, because it is not useful to its citizens. By opting for lights out in the middle of the night, Sauliac-sur-Célé has killed two birds with one stone: reducing its bill and attracting admirers from the celestial vault. The reduction of light pollution allows the development of astrotourism, in which the Occitanie region is a reference. It is one of the largest reserves starry skies of Europe. This label is awarded by the International Dark-Sky Association and rewards a starry sky with a “exceptional quality”.
“There are many amateur astronomers who come to our town to observe the sky.”
Daniel Bancel, mayor of Sauliac-sur-Céléat franceinfo
France has four reserves of this type: the Pic du Midi (Occitanie), the Cévennes national park (Occitanie), the Alpes Azur Mercantour reserve (Provence-Alpes-Côte d’Azur) and the regional natural park of Millevaches ( New Aquitaine).
Beyond the economic and energy gain, the reduction public lighting can therefore be an asset of attractiveness. “We are a region with 50,000 new inhabitants each year, we had to think about night tourism”concludes Agnès Langevine, vice-president in charge of climate for the Occitanie region.