Co-financed by the European Union. Connecting Europe Facility – CEF
European Union
Driving towards low carbon mobility

Reasons for Using Natural Gas in Transport

The use of Natural Gas in engines for transportation started as early as the 1930s, but the first period that saw a significant activity began in the 1970s, when Natural Gas was seen as a secure fuel in the aftermath of the oil crisis. Since that period, Natural Gas Vehicles (NGVs) have entered and exited the stage of several countries/regions in different periods, while technology and transport applications continued to evolve.

Some relevant reasons for Natural Gas for its use as a fuel in the transportation sector include:



• Almost 85 countries from all five continents use NGV/CNG.
• More than 20 million vehicles run on this noble fuel today.
• Cars refuel at over 25 thousand filling stations spread throughout 2,900 cities worldwide.
• 180 OEM NGVs are offered by vehicle manufacturers. OEMs’ interest is growing: Ford, Scania, Opel, GM, Mercedes Benz, Toyota, Hyundai, Tata, Fiat –among others- are clear examples.
• Natural gas exploration keeps expanding. Coal bed methane constitutes a new alternative. Methane hydrate reserves on the sea bed are countless and several times larger than traditional reserves.
• Gas pipelines networks are widely expanded across Europe and continue to develop.
• The use of mobile natural gas pipelines –on trucks or trailers- makes NGV/CNG available where there are no physical pipelines either because of long distances or because of the scale of the demand.
• CNG refueling points can be established at the existing petrol station.
• In typical NGV/CNG refueling stations, owners do not have to rely on the arrival of trucks for the fuel supply since it is constantly provided by the pipeline.
• It is possible for some users to refill their NGV/CNG cars at home because there are dispensers that take natural gas directly from the domestic distribution network.
• Natural gas for vehicles may replace all liquid fuels in all their applications and more, whereas the opposite is not possible
• Regarding land transport, there are cars, vans, scooters, motorbikes, tricycles, all types of buses and trucks that run on this fuel.
• In addition, cranes, farm machinery, snowcats, planes, light aircraft, motorboats, ferries, and trains –among others- are already NGV/CNG-propelled successfully.
• Natural Gas price is extremely stable.
• More and more governments promote natural gas as the core of their energy matrix to break the dependence generated by the permanent liquid fuel importation.
• Countries that import fuels have to pay 50% less for natural gas (LNG) than for liquid fuels like diesel (per equivalent unit of energy).
• Natural gas is the only abundant, eco-friendly, economically viable fuel with the infrastructure required to supply the world’s automotive fleet for the next 40 years.
• The world average indicates that driving an NGV is 60% cheaper than using a gasoline vehicle and 33% more economical than diesel.

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• NGV/CNG engines produce 25% less carbon dioxide than gasoline and 35% less than diesel. CO2 contributes to global climate change due to the greenhouse effect.
• They reduce carbon monoxide emissions by 95% compared to gasoline, hydrocarbons emissions by 80% and nitrogen oxides’ by 30%.
• CNG does not contain Sulphur, particulate matter, lead or heavy metals traces.
• CNG cylinders are hermetically sealed receptacles, while by using gasoline, part of it -contained in the tank- evaporates. This causes almost half of the contamination by hydrocarbons associated with the vehicular application.
• Unlike gasoline, natural gas for vehicles does not have toxic additives of organic lead or benzene, the latter being highly carcinogenic.
• Natural gas is not toxic or corrosive and does not contaminate groundwater at all. That is why there is no environmental risk in case of leakage, contrasting with the harmful environmental effects brought about by oil spills.
• NGV/CNG engines decrease noise pollution by having a smoother and more silent performance than gasoline engines and especially diesel ones.
• Biogas (methane from the breakdown of organic matter) turns natural gas into a renewable fuel that can be produced in the whole world. Biogas production from agricultural goods yields four more times per hectare than liquid biofuels.
• Natural gas complies with the strictest environmental standards required by governments and regulating agencies. It is the large-scale use of fuel with the lowest contamination levels.
• It is the necessary bridge to hydrogen, given its molecular structure and the logistics required for its implementation



• NGV/CNG is not new technology. It has 70 years of history. It is widely proven and its technological advances are constant.
• Being lighter than air, in case of eventual leakage, compressed natural gas rises and rapidly dissipates. Instead, gasoline spills and moves downwards, which increases fire and explosion risk considerably during an accident or leakage.
• CNG requires a 600º C temperature for ignition while gasoline and liquefied petroleum gas ignite at 450º C. This is the reason why it is much more improbable that an NGV catches fire, under any circumstance.
• The fuel circuit for natural gas is hermetic and has no air inside. Therefore there is no spontaneous ignition. On the contrary, in liquid fuel tanks, there is always a flammable mixture, since they are open to the atmosphere.
• Cylinders are manufactured under very strict safety norms and are subject to tests with pressures much higher than the ones existing during a regular refilling. Design and testing pressure is 300 Bar, they do not explode at less than 460 Bar, and the working pressure is 200 - 220 Bar.
• Due to their robustness, structure, shape and location inside the vehicle, cylinders are much less dangerous than a gasoline tank in case of collision. All cylinders undergo tests with fire and firearms.

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•Natural gas for vehicles has a higher octane number than gasoline (125 vs. 90), which provides combustion without self-ignition, even in engines of higher compression and efficiency.
• Furthermore, combustion is total, because the mixture between CNG and air is perfect at any ambient temperature.
• The oil that lubricates the engine is less contaminated if natural gas is employed, and intervals between oil changes are twice as long.
• There are no sediments and the spark plugs are kept clean. The walls of the engine cylinders are not washed, which results in better and more effective lubrication.
• Combustion gases are not corrosive. By not damaging metals, the life of the exhaust pipe and silencers is longer.
• The gaseous nature of the fuel eliminates the scanning actions in the cylinders during fast acceleration periods, with the advantage of reducing the corrosion of metal surfaces.
• The engine presents great performance flexibility during accelerations without irregularities or backfires, even at low direct speed.
• Converted vehicles may switch from using NGV/CNG to gasoline by simply pushing a button or automatically while driving.
• NGV-gasoline bi-fuel system doubles the car’s driving range.
• NGV/CNG works fine under any climate condition. Since the fuel does not freeze –not even at low temperatures- the vehicle will always be ready to be used. NGV/CNG components are tested at -40°C during its approval process. Natural gas only liquefies at 165 °C.