At the exit of Saint-Omer (Pas-de-Calais), along the A26 motorway, which heads towards Boulogne and the sea, the Porte-du-Littoral business park is preparing to welcome a new industrial establishment. An agri-food factory should see the light of day in September 2023, with 25 employees, perhaps 75, in the long term, if all goes well. Today, the site is under construction: the foundations are dug to the limit of the 9 hectare plot, the space optimized to the maximum.

On the neighboring plot of 4 hectares, three companies, two in the food industry and one in ironwork, have been announced. Everything looks like a construction game with buildings nested inside each other to save space, a single parking lot, a single water treatment unit and a single fire reserve for everyone.

Because, today, the watchword is to densify in order to save this resource that has become scarce: land. Far, very far from the principles that governed the establishment of another factory, a few hundred meters away. Set up in 2015, SOS Oxygène lives offshore. Around the building, a huge parking lot three-quarters empty, a vast lawn of some 7,000 square meters: the land reserve “in case” the company should one day expand. Christian Leroy, president of the community of communes of the Pays de Lumbres, designates the other business premises which line up on the other side of the motorway, each surrounded by their hedges, their lawned square and their curtain of trees. “Today, factories have to be grouped together to save space, whereas before we were told that we had to hide them, integrate them into the landscape. »

10% of the land is now artificialized

This was before the zero net artificialisation (ZAN) system. Included in the Climate and Resilience Law of August 2021, it aims to preserve biodiversity and limit soil sealing. To do this, the law requires territories to reduce by 50%, by 2030, the rate of artificialization of land, natural, agricultural or forest areas. An objective that applies to everyone and to all human activities, whether housing, infrastructure, public facilities, and therefore also economic. But “the real subject is still the industry. Where will we put them, the factories, tomorrow? asks Christian Leroy.

At the scale of France, 10% of the land is artificialized today – which makes it the most concrete country in Europe per inhabitant. Housing covers 42%, transport infrastructure, 28%, and industry, 4%, according to figures from France Strategy. The National Institute for Geographic and Forest Information (IGN) is also starting to publish a reference database for the description of land use throughout the territory, with the aim of covering the All of France in 2024.

Until then, the implementation of the ZAN means that all these activities will have to share, over the next ten years, approximately 125,000 hectares. Half less, therefore, than the 250,000 “consumed” for ten years. A “significant effort”, underlines Vincent Le Rouzic, deputy director of studies at the think tank La Fabrique de la cité. “The challenge is therefore to manage to reconcile the objectives of land sobriety with others such as housing or reindustrialization. »

“Tomorrow everyone will have to have work”

If no one disputes – at least out loud – the merits of this system, it gives a hard time to elected officials or industrialists, at a time when reindustrialization is set up as a national priority. Twenty years ago, when the crystal factory of Arques (Pas-de-Calais), the industrial flagship of the Saint-Omer region, was shining brightly, it employed 16,500 people. Today, it has only 4,500 workers. “We are in a territory where the population continues to increase, people have many children”, notes François Motte, president of Sofie, the economic development agency of the country of Saint-Omer. “Tomorrow everyone will have to have work. The investors are there: the Belgians come from neighboring Flanders to look in France for a quality workforce and a water resource that they no longer have – we are in a land of marshes. The British would also like to set foot on the continent to get closer to their customers and avoid post-Brexit customs hassles.

In 2021, the Sofie agency studied some 340 location files, validated around forty and thus “consumed” 22 hectares of land on the territory of the community of municipalities. To comply with the ZAN system, there are now some 45 hectares available, enough to “hold out” for about two years – and again, “the largest plots are only 10 hectares”.

Impossible to accommodate major projects, with their processions of subcontractors and induced jobs. “Even for small businesses, it’s hard to find land,” says Motte. “So ‘gigafactories’ aren’t even worth it. These giant factories, which require at least 15 to 20 hectares, have little choice but to set up on former industrial sites. Thus, in Douvrin (Pas-de-Calais), the Stellantis battery factory, which will open in 2023, is thus under construction on the former site of Française de Mécanique, while Envision, in Douai (Nord) , took place on the land reserve of the Renault factory.

Find other solutions

Another difficulty, the territories must also include in their artificialization assessments the infrastructure projects decided at the national or regional level. “We are going to build a gendarmerie in a village, that’s very good, but it takes us 3 hectares,” said Joël Duquenoy, president of the Saint-Omer urban community. The elected official pleads that projects “from above”, such as public services, port areas, infrastructure or “Brexit car parks”, are not counted as the rest of the land.

A “major challenge”, according to him, to preserve the economic development of the territories, especially since the ZAN system must be applied uniformly throughout the country, regardless of density, economic structure or local needs. “We should be able to work more finely at the level of each territory,” concedes Mr. Le Rouzic. To do this, La Fabrique de la cité is considering proposing a system of “rights to artificialize” that local authorities could exchange, according to their needs.

Due to a lack of land resources, other solutions must therefore be found to accommodate industrial activities and their jobs. For example, by pooling equipment, increasing the density of plots or building factories at height, but this requires additional investments and digging deeper foundations.

The Climate and Resilience Law also offers the possibility of using wasteland, not without having depolluted at great expense. With deindustrialization helping, France is not lacking in it: it has around 100,000 hectares of disused sites, enough to relocate a good number of factories. But, here again, it is the distribution on the territory that poses a problem. In Saint-Omer, the few that exist are in the city center: impossible to put industrial activities back there, except to provoke the anger of the local residents.

At the level of the community of municipalities, an approach has been initiated to find solutions, for example by turning to abandoned agricultural buildings, without encroaching on cultivated land, to accommodate light industry. “We had a feeling, for a few years, that we were going to have to consume less space. We are now faced with this societal problem,” summarizes Christian Leroy.