Driving cleaner thanks to green hydrogen

Today we rely heavily on electric vehicles to reduce greenhouse gases, but there is another source of energy: hydrogen. Not just any. This hydrogen is made from sewage sludge from a sewage treatment plant. A company from Montpellier has developed this innovative process on demonstration in Hyères, near Toulon.

On the site of the Hyères wastewater treatment plant, in the Var, a strange container: here is VaBHyoGaz, the brand new prototype for the production of green hydrogen invented by a Montpellier company, Seven, and tested by Veolia.

A revolutionary technology that makes it possible to produce hydrogen from sludge from the treatment plant to supply vehicles with fuel. Green energy. Its raw material comes directly from our organic waste.

For this residual sludge to become hydrogen, it is necessary to go through an initial transformation process.

They are first sent to a methanizer. In this huge round tank, the organic matter is heated and in the absence of oxygen, its fermentation will produce biogas.

This is the starting point for the production of hydrogen, as explained by the leader of this project at Seven.

We will recover this biogas in our process. We’re going to mix it with water. We bring everything to 800 degrees. This happens on a catalyst that will allow the steam reforming chemical reaction to take place. This consists of breaking the molecules of biogas and water to obtain hydrogen and CO2.

Cyrille Ridart, hydrogen project manager at Seven

Thanks to this process, it is therefore possible to produce a source of carbon-free and renewable energy. And this energy that will be used to make fuel is also a local solution. It recovers the territory’s waste for use in the territory. A fine example of a short circuit.

There are other ways to produce hydrogen but their impact on the environment is not neutral.

It can be produced using a by-product of the oil industry (gas, oil or coal) but it is obvious that using a fossil material to produce hydrogen is not the solution to have a good carbon balance. . Another option: it can be produced using electrolysis, but this technique requires much more water and electricity. And it is very expensive.

Veolia, which operates the Hyères wastewater treatment plant, is interested in this process because it offers a new way of ecological recovery for its biogas.

For the moment, it is simply used to supply the boiler which heats the methanizer. In other cases, it can be used for generators that will produce electricity or be injected into the GRDF gas network.

Hydrogen production is a new use for our wastewater treatment plant. This allows us to become a fuel supplier and provide an energy solution for green mobility.

Alain le Divenach, development director for major Veolia projects

Pour also recover CO2 released during the production of hydrogen, Veolia has set up a algae production prototype, which thrive on carbon dioxide. If the pilot is conclusive, they could be used to feed fish.

The company’s prototype Seven delivers 10 kg of hydrogen per day, enough to allow a light vehicle to travel around 1000 km.

In order not to throw away its production and for the purposes of the demonstration, Veolia has invested in a utility vehicle, powered by hydrogen.

The principle is simple. Under the hood is a fuel cell that replaces the batteries. It is she who will be charged with hydrogen and produce electricity to run the engine.

On the road, this vehicle, which was charged in a few minutes, drives without emitting any C02 emissions responsible for greenhouse gases.

It only releases water. You can see it by the little drain pipe under the car. The big advantage is that there are no batteries that take up a lot of space like in traditional electric vehicles. It is very pleasant to drive, without noise and without vibration.

Stéphane Pedeux, operations technician at Veolia

But this source of energy is primarily intended for trucks, coaches, goods transport or even household waste dumpsters. Because the heavy mobility sector particularly needs to be carbon-free and electric is not suitable for these uses.

It takes several hours to charge an electric vehicle and in the transport sector, immobilizing a truck or bus for too long is not the solution. He needs to be available immediately. In addition, hydrogen gives vehicles a very long range, which is a big advantage.

Cyrille Ridart, at hydrogen project at Seven

The interest of hydrogen also lies in its price. A kg of hydrogen would cost 9 euros. We could therefore do 100 km at this price. If we compare with a vehicle that runs on diesel, displayed on average at 2 euros, and which consumes an average of 6 liters per 100, it therefore costs 12 euros. The economy is interesting.

Within 2 years, Seven will go from prototype to industrial scale. The first green hydrogen production and distribution stations will see the light of day in Occitania. Two of them are already under construction in the Tarn.