Le GNV, un carburant écologique

What is NGV?

Natural Gas Vehicle, or NGV, is an alternative to oil. Originally, NGV was reserved for professionals, but the market has opened up to individuals. NGV can be found in two forms:

Compressed Natural Gas (CNG), which circulates in the public network and supplies service stations
Liquefied Natural Gas (LNG), which is liquefied at 160°C and transported by tanker

What is Natural Gas for Vehicles made of?

NGV is composed of 97% methane (CH₄). This gas, low in carbon, has several advantages related to the environment. Indeed, NGV used as fuel emits 15% less greenhouse gases, compared to diesel for example.

BioNGV, which is also largely composed of methane, has the advantage of being considered "renewable". Indeed, generally obtained by methanization, bioNVG has a real advantage: that of being able to valorize local waste. Indeed, thanks to methanization, agricultural waste or green waste, from household waste, sewage treatment plants (sludge), agricultural productions, etc., can be used and transformed. As a result of this methanization, bioNVG is obtained.

As part of a virtuous circle in terms of ecology, NVG can be considered as renewable energy.

Can it replace other fuels?

Today, NVG is used in any kind of vehicle, either originally designed to run on NVG or equipped with a NVG kit: trucks, vans, buses, cars, etc. As a good alternative to other energies (diesel, gasoline, electric, etc.), NVG is gradually becoming established.

For private individuals NVG is quite economical and will be quickly adapted to a majority of vehicle engines. Even if for the moment private customers are mainly focusing on electric vehicles, it is possible that NVG will gain momentum in the next years.

For professionals, especially in transport and logistics, electric energy is not suitable for all vehicles. NVG is therefore preferred for heavy and commercial vehicles, whose engines are not developed for electric power.

NVG seems to be able to replace other fuels in the medium/long term. Today, in France, nearly 32,000 vehicles run on NVG.

Did you know that?

The cars currently available on the market are called bi-fuel gas/petrol vehicles, since they run on both energies. With a gasoline tank and a NVG tank, the autonomy of this type of vehicle is greater than that of a conventional vehicle. In fact, the NVG range (200 to 500 km depending on the vehicle) is added to the gasoline tank capacity.

The vehicle runs primarily on NVG and switches automatically to gasoline when the NVG tank is empty.

What are the advantages of CNG?

Economic benefits:

NVG is cheaper than other fuels to buy
A NVG engine has a longer life than a gasoline or diesel engine

Environmental benefits:

15% less greenhouse gas emissions compared to diesel
Less fine particle emissions

As said before, NVG has many impacts on the environment. We talked about the decrease of greenhouse gas emissions or fine particles, but it is also important to know that NVG does not give off smoke or unpleasant smell. Moreover, a NVG engine is quieter than a gasoline or diesel engine, which reduces noise pollution, especially in the city.

Moreover, bioNGV, through its production, allows the recovery and use of local waste, which is a very positive impact for the environment.

What does the law say?

The decree n°2022-423 of March 25, 2022, relating to the exceptional aid for the acquisition of fuels, provides for a reduction in the price of fuels, including NVG, both compressed and liquefied.

But then, if it is so advantageous economically AND for the environment, why don't we all drive with CNG?

First of all, it is important to know that the number of existing NVG vehicles is still very low, because manufacturers are hesitant about the success of this motorization. Moreover, there are risks related to its production, storage and handling.

What are the risks of NVG?

Risk of cold burns

LNG (Liquefied Natural Gas), stored at very low temperatures (-160°C), carries the risk of burns. It is mainly used in trucks and ships, and therefore in a professional context.

To protect yourself: Persons handling LNG during refueling procedures must wear gloves when coming into contact with cold-stored equipment. Goggles or a visor are also recommended.

Risk of fire and explosion

NVG is a combustible gas. In a confined space, it can ignite if the concentration of NVG in the air is between 5 and 15% and if it is associated with oxygen and a heat source (Fire Triangle Principle).

To protect oneself: Stations or maintenance workshops are in general ventilated spaces, NVG will present little risk because it will tend to disperse. However, it is preferable to equip operators with portable gas detectors and premises with fixed gas detectors to protect them from the risk of explosion or fire.

==> See our case study at the end of the article

Risk of anoxia:

In a confined environment, if the concentration of the gas-air mixture is higher than 25%, NVG replaces the oxygen in the ambient air. It then acts as an asphyxiant gas by depriving oxygen.

To protect yourself: Operators must wear Personal Protective Equipment, including respiratory protection.

Risk of leakage:

On a NVG system there is a risk of leakage, caused by temperature and pressure variations. Indeed, leaks can appear at low pressure and disappear at high pressure. In order to avoid this, the pressurization of the circuit is systematically done in stages.

To protect yourself: To check the tightness of the circuit, electronic detectors, in this case leak detectors, are highly recommended. Indeed, they allow a regular control on the circuit.

Case study : Natural Gas Vehicle (NGV) Bus

NVG buses in France

NVG is the most common alternative fuel for bus propulsion. Nowadays, 17.30% of urban buses run on NVG in France. This represents an average of 4500 buses out of a total fleet of 26000 buses, compared to 2613 NVG buses in 2014. A remarkable evolution over the last 8 years up to 70%.

Source: ADEME and GRDF (2016)

Why have large cities chosen NVG buses?

An environmentally friendly fuel

NVG buses are an excellent option compared to diesel equivalents and more than meet the requirements of the Euro 6 standard.

This standard, which has been mandatory for heavy-duty vehicles since January 1, 2014, imposes acceptable vehicle emission limits for certain pollutants.

> It requires an additional reduction of the maximum values of 80% for nitrogen oxides, 50% for particulates and more than 70% for hydrocarbons.

NVG Buses emit :

97% less nitrogen oxide (NOx) emissions
13% less carbon dioxide (CO₂) emissions than Euro 6 Diesel Buses.
Concerning particulate emissions (PM10 and PM2.5), they are so low that they cannot be measured.

> We can therefore affirm that NVG buses are the least polluting in their category.

NVG buses are half as noisy as a diesel engine, they represent 175 tons less greenhouse gas emissions per year, 40 to 50 cars less at peak hours and 70,000 liters of fuel saved annually. Running a bus on biomethane as a fuel allows to push the balance of these vehicles even further. Legitimately, NVG/BioNVG buses obtain the Crit'Air 1 sticker which authorizes access to all ZEP (Zones à Faibles Transmissions).

The IDF Mobilité (Ile de France transport network) has made a real ecological change thanks to NGV and BioNGV and has set itself the goal of becoming the first European metropolis with 100% decarbonized public transport.

An economically attractive fuel

NVG has seen its price triple in less than a year, due to a very high global demand following the Covid and supply difficulties due to the current geopolitical situation. But it remains for the moment lower than diesel and more affordable than an electric bus.

Also, NVG is subject to the Taxe Intérieure de Consommation du Gaz Naturel (TICGN): The rate applicable to natural gas for fuel use is indicated in Article 266 quinquies of the Customs Code.

Its rate will remain constant in 2022 and will encourage the development of NVG trucks.

For the moment, the amount of the internal consumption tax on NVG is 6 times lower than the professional diesel and 8 times lower than the diesel rate (subject to the TICPE): see the table opposite*.

* The figures presented are from the beginning of 2022, they show the trend of CNG development. Unfortunately we cannot say that this is still the case today because of the current geopolitical situation and the increase of gas prices.

NVG Bus means equipped and regulated stations

The Bus Stations or Operational Centers (BOC) are depots in charge of the storage and maintenance of road vehicles, which must equip each of their parking spaces with a NVG or biomethane recharging outlet as well as having the support of a natural gas production chain.

But that's not all, the arrival of NVG buses implies changes associated with ATEX regulations for the supply and maintenance of buses and also with ICPE regulations for the protection of the environment.

Between the 97% methane composition of NVG and the regulations, there are gas risks: dangers related to the formation of explosive or asphyxiating atmospheres. Thus, controls must be established in the stations, before they are put into service. And thus to ensure the conformity and the placement of the safety devices according to the particularities of gases, like the fixed gas detectors, the mobile gas detectors or the extractor fans.

An audit, carried out by an authorized engineering office, will allow the updating of the obligatory documents to guarantee the safety of the personnel: DRCPE (Document Relative to the Prevention Against Explosions) and DU (Single Document). It will allow us to measure the effects from a regulatory point of view, in accordance with labor law and ATEX preventions.

Focus on regulations

The ATEX regulation requires to control the risks related to the formation of explosive atmospheres (ATEX). The risk is quite low because the conditions of explosion are rarely met simultaneously; but it should not be underestimated. The regulations require CNG stations and maintenance workshops to train employees on the risks and to implement safety devices to control the dangers of explosive or asphyxiating atmospheres. And thus ensure the compliance and placement of safety devices according to the particularities of gases, such as fixed gas detectors, mobile gas detectors or extractor fans.

The ICPE regulation (Installation Classified Protection of the Environment) imposes that the station is subjected to certain safety distances between the equipment and the station and also with a building receiving the public. The other criterion is the noise nuisance, the station must be far enough away to limit noise in relation to residential areas.

Gas detection in CNG stations

According to the regulations, it must measure 100% of the gas explosive range and be triggered at 0.5% of natural gas in the atmosphere according to article R. 232-1-7 of the Circular of 09/05/85 relating to the technical commentary of decrees 84-1093 and 84-1094 of 7/12/1984 for the ventilation and sanitation of workplaces. It is also notified that the safety device must be installed and subjected to regular maintenance by approved technical agents and that outside of ATEX zones and zones controlled by a fixed or mobile device, workers on vehicles must also be equipped with portable gas detectors.

Gas detection is highly regulated, so how do you choose the right detection?

Between the different technologies, the catalytic detection which measures the concentration of gas using a catalytic oxidation filament, the infrared point detection which measures thanks to the wavelength of the gas and the MPS detection which measures via a cell of new technology Molecular Property Spectrometer. Between the different scenarios because each station is different? How to know which sensors, which servos (sound and/or visual signals)? Do we need backup generators? A supervision system? Detection barriers?

All these questions are legitimate, which is why we offer a "turnkey" solution to support you in the energy transition by leveraging our technical skills and expertise.

We help you understand the analysis of these risks and propose you the technology adapted to your needs and set up the detection scenario according to your configuration.

You are a vehicle manufacturer, a local authority, a garage dedicated to trucks and transporters with a CNG project?

Do not hesitate to contact us to define your security expectations with our experts:

We accompany you on the recommendation and supply of equipment
We coordinate the implementation work with our network of electricians
We commission the installation and check the connections
We follow the installation throughout its life thanks to the implementation of a maintenance contract.