The Nice olive has unsuspected virtues. In Broc, in the Alpes-Maritimes, where the cultivation of this black gold is a religion, “nothing is lost, everything is transformed”: the fruit of the olive tree is also used to raise the temperature in several public buildings connected at the boiler room of the municipal mill. On site since 2016, work has been done to be able to burn, in addition to the traditional pellets, the residues of the oil pressing.
These “pomace” were until then “taken to the recycling center without any recovery” and it is the “environmental vocation” of the project that first seduced the municipal council, recalls the mayor without label Philippe Heura. Today, its economic aspect is also a “real plus” for this small village of 1,400 inhabitants which, like other communities, has to face soaring energy prices.
The initiative would have already enabled the town hall “to save around 9,000 euros in electricity for heating the buildings and 12,000 euros for the elimination of pomace”. A crèche, the media library, the music school, ie 1,000 m2 of space, benefit from it. The boiler of the mill, necessary for its operation, is also supplied.
A raw material available, without transport
The initial investment, i.e. 15,000 euros, “was amortized after five years according to our calculations” and “pomace today offers us a supplement that allows us to limit the increase in the cost of pellets”, adds the aedile. In concrete terms, a machine capable of separating the pulp from the pits has been installed. And the raw material is available directly on site. Without any need for transport.
“As the mill grinds around 200 tonnes of olives per year, we can expect a production of 35 to 40 tonnes of crushed pits, which makes it possible to meet local demand for heating public buildings, with a good margin of manoeuvre. for the less prosperous years”, indicates the municipality.
In years when harvests are less important, the community can draw on its stocks. And everybody is happy. “People who entrust us with their olives are delighted to know that they are also used to heat municipal buildings, supports Brigitte Bourreaud, the director of the mill. It’s a virtuous circle. »
It can damage conventional boilers
The system has already attracted other towns also close to Nice, such as Gillette and Tourretes-Levens. But, “it is still a complicated and above all expensive solution to implement, especially for small communities”, tempers Jean-Luc Belliard, head of the water and environment center at the Alpes-Maritimes Chamber of Agriculture. “The advantage of pomace, its very good calorific value, is also its weak point. By heating very strongly, it can damage conventional boilers, so it is necessary to install over-equipment to avoid accidents. And then, the seasonal aspect is obviously to be taken into account, ”notes the specialist.
Another solution exists so as not to lose the pomace without having to make any particular investment. Mixing them with the pellets, without exceeding a maximum of 10% of the total. This way, there is no risk of damaging the equipment.