The cultivation of industrial hemp has almost disappeared in France, but it has been revived by new uses, including building insulation and bioplastics, to provide industries with a low ecological footprint.
Hemp cultivation occupied up to 176,000 hectares in 1860, mainly for canvas and paper, but fell to 700 hectares in 1960. Today, hemp is grown by nearly 1,500 farmers on 17,000 hectares. The six Hexagonals, private or cooperative, process and market 100,000 tons of fiber.
Cavac Biomaterials, a subsidiary of the Vendée cooperative of the same name, has set up a plant in Sainte-Gemme-la-Plaine, near Luçon, to transform the raw material into insulation, bulk or panels, to directly supply the building sector.
12 years ago, the Cavac "wanted to go downstream by creating an industrial sector to find outlets for the products of its cooperators" and capture the added value, says its president Jerome Cailleau.
"Hemp has become essential," he says, first of all for its agronomic properties: it is an annual crop that lighten the working time of farmers, and grows without pesticides or irrigation.
"Hemp fits perfectly into the rotation system" of crops, says Jean-Marie Gabillaud, farmer in Vendée, because "the field is cleaner and the yield is higher on the culture of after".
Another argument in favor of hemp, the possibility of diversifying with a non-food, renewable, which captures CO2, "while responding to the rise of taste for natural materials," said the president.
"In 2009, we started from scratch", everything was to be built in the sector, from the learning of production methods by farmers to industrial processing. Between the crisis of the building, the fire of the building and the difficulties to obtain a certificate of production, the beginnings were difficult, testifies Olivier Joreau, deputy general manager of Cavac.
– fiber and hemp –
Today, about 150 cooperators cultivate 2,000 hectares of hemp within a radius of 100 kilometers around the plant. It employs 45 people and produces 15,000 tonnes of insulation and other co-products per year.
The hemp bales are passed several times in machines that separate the fiber from the hemp, the rigid inner part of the stem, which allows in particular to make hemp concrete.
The fiber is in turn mixed with a binder, refined, combed, and cooked. It is then packaged in rolls or plates of variable thickness of ready-to-install insulation.
"The production tool is running," says Joreau, who says he is "very confident in the future".
Since the creation of the plant, the evolution of regulations concerning low-energy buildings and the better consideration of the carbon footprint of materials play for hemp insulation.
There remains the problem of the extra cost that this material represents, estimated at 10% by the interprofession.
To overcome this constraint, we "expect financial or fiscal incentives from the state," says Joreau, because the goal is to "take market share of traditional insulation" based on non-renewable materials.
It is also necessary to make itself known, and for this, the interprofession pushed professionals of the buildings and the industrialists to be candidates for the construction of the Olympic village in Saint-Denis and the buildings for the press with the Bourget for the Olympic games of 2024.
"The idea is to use these buildings, which do not require air conditioning or heating, as showcases of know-how" of the sector, says the director of InterChanvre Nathalie Fichaux.
"Bringing into the heads that summer comfort is as important as the comfort of winter, and choosing the athletes to demonstrate it, it would be great," says the president of the association Build in Hemp, Jean- Claude Daniel.