Natural Gas Car: A sensible alternative to petrol and diesel vehicles?

Brief overview: Natural gas car

Image result for natural gas car

  • A natural gas vehicle is a vehicle whose conventional gasoline engine is powered by natural gas, not gasoline.
  • The natural gas used is so-called CNG, a high pressure compressed natural gas.
  • CNG is the abbreviation for the English term “compressed natural gas”. For this reason, natural gas vehicles internationally referred to as CNG Vehicle.
  • The compression of the gas for the operation of vehicles is necessary because natural gas in natural form does not have sufficient energy density.
  • If the gas is compressed, the energy density increases. Thus, the required tank volume is reduced.


Distribution in Germany

According to data from the Federal Motor Vehicle Office (KBA), there were more than 97,000 natural gas vehicles in Germany in 2016. Thus, the number has almost quadrupled compared to 2004. However, if these figures are compared with the total of 45.8 million cars that were approved by the KBA on 1 January 2017, it is clear that natural gas vehicles in Germany have only a very limited distribution. As a result, only two out of every 1,000 cars are natural gas vehicles.

Why the number of natural gas cars in Germany is not higher, can be attributed to various reasons. For one, the initial cost of these cars are usually higher. On the other hand, the coverage with natural gas filling stations is by far not as high as with other fuels.

However, there is an initiative on natural gas mobility of the European Commission. It aims to increase the number of natural gas vehicles within the EU by 2020 to 1.4 million.

Natural gas vehicles of common manufacturers

model power
Audi A3
Sportback g-tron
81 kW (110 hp)
Fiat Punto
1.4 8V Natural Power
57 kW (77 hp)
Fiat Panda
0.9 8V TwinAir
59 kW (80 hp)
Fiat Qubo
1.4 8V Natural Power
51 kW (70 hp)
Fiat 500L
0.9 8V TwinAir
Natural power
59 kW (80 hp)
Fiat Doblo
1.4 16V Natural Power
88 kW (120 hp)
Mercedes-Benz B 200
Natural Gas Drive
115 kW (156 hp)
Mercedes-Benz E 200
Natural Gas Drive
115 kW (156 hp)
Opel Combo
1.4 Turbo CNG ecoFLEX
88 kW (120 hp)
Opel Zafira Tourer
1.6 CNG Turbo ecoFLEX
110 kW (150 hp)
Seat Mii Ecofuel
1.0 start & stop
50 kW (68 hp)
Seat Leon
1.4 TGI Start & Stop
81 kW (110 hp)
Seat Leon ST
1.4 TGI Start & Stop
81 kW (110 hp)
Skoda Citigo
1.0 CNG Green tec
50 kW (68 hp)
Skoda Octavia
1.4l TSI G-TEC
81 kW (110 hp)
VW eco up
1.0 EcoFuel
BlueMotion Technology
50 kW (68 hp)
VW caddy
80 kW (109 hp)
VW Golf TGI BlueMotion 81 kW (110 hp)
VW Golf Variant
TGI BlueMotion
81 kW (110 hp)
VW Touran TSI EcoFuel 110 kW (150 hp)
VW Passat TSI EcoFuel 110 kW (150 hp)
VW Passat Estate
TSI EcoFuel
110 kW (150 hp)

How does a natural gas car work?

A natural gas car has a conventional gasoline engine. In the cylinders, a gas-air mixture is burned, which in turn sets the drive shaft in motion. It replaces the mixture of gasoline and air.

Both monovalent and bivalent natural gas cars are commercially available:

  1. Monovalent: In this case, the vehicle will be run on natural gas only. In this way, a significantly higher engine performance can be achieved and the natural gas consumption can be reduced. A petrol tank is only available for emergencies and intended, for example, for the trip to the nearest natural gas filling station.
  2. Bivalent: These cars can run on both natural gas and gasoline. The additional fuel tank bivalent cars are more independent and have a longer range. However, consumers have to accept a few performance losses.


A natural gas car is fueled at a gas station like a gasoline car via a gas pump. For this purpose, the nozzle is placed on the tank opening. Only when all closures are properly tight, the refueling process starts. For this purpose, the conventional natural gas is compressed from the natural gas network.

The compressed gas is dried and placed in a buffer. This prevents icing while refueling. Refueling takes just as long with natural gas as with diesel or gasoline.

At some natural gas filling stations, natural gas is added to fossil natural gas. This is gas that is extracted from natural substances in biogas plants. After refining, the gas is fed into the natural gas grid. Some manufacturers like Audi are also working on synthetic biogas.

Natural gas is not the same as LPG

Often, natural gas vehicles are confused with cars that refuel LPG. However, there are clear differences between LPG and CNG.

LPG is liquefied petroleum gas consisting of propane and butane. It is commercially available as so-called LPG. This is the abbreviation for “Liquid Petroleum Gas”. A natural gas vehicle can not be refueled with LPG. Similarly, a car powered by LPG can not be operated with CNG.

Like natural gas, LPG is also reduced by tax exemptions. However, LPG is produced on the basis of crude oil. Thus, LPG is bound to petroleum and dependent on oil production. In operation, less nitrogen oxides are produced than with gasoline. However, the CO2 emissions of LPG are significantly higher than those of natural gas.

Conversion to natural gas operation

Vehicles with gasoline engines can be converted into a natural gas car in a specialist workshop. You then have the opportunity to drive with both types of fuel. As a rule, there is a conversion for bivalent operation with gasoline and natural gas.

Additional insurance for retrofitting


If you have your car converted to natural gas, you may lose the manufacturer’s warranty for the engine. It is also possible a loss of warranty for the entire drive. For this reason, you should take out additional insurance, which covers possible damage caused by the conversion. Engines with gasoline direct injection and diesel engines are hardly or only with great effort to convert. As a rule, retrofitting is not worthwhile here.


Before the conversion, a special exhaust gas analysis is usually carried out. After that supply systems to the engine and valves must be changed. In addition, the installation of gas tanks. Most of these are installed below the rear seats. Special safety devices ensure that the pressure vessels remain safe.

After conversion, the conversion must be approved by TÜV or DEKRA. In order to avoid additional approval special retrofit systems may be used which are already pre-approved. You then have the approval ECE-R 115.

An expert also checks the converted vehicle as part of a “gas system installation test” (GSP). The cost is around 100 euros.

Further costs may arise from a mandatory inspection of the tanks. These must be checked by the TÜV every three or five years, depending on the model. For this purpose, up to 600 euros are due.

The conversion itself costs you depending on the car model with 3,500 to 5,000 euros. As a rule, however, an engine conversion has amortized after about 60,000 kilometers.

Insurance and costs

Natural gas cars are available for less than 15,000 euros, for example from Fiat. Other manufacturers such as Mercedes or Audi charge higher prices. Thus, a natural gas vehicle in the premium segment with appropriate additional equipment can cost more than 50,000 euros.

  • Taxes : Thanks to tax incentives, natural gas itself is significantly cheaper than conventional fuel. For the purchase of a natural gas vehicle, there are no tax benefits. Vehicle tax is generally much lower for natural gas vehicles, since the tax is based not only on engine capacity but also on CO 2 emissions. Since gas passenger cars emit only very little CO 2 , car taxes are falling.
  • Profitability : On the Internet, there are numerous calculators, with which you can decide whether a natural gas car can pay off for you.
  • Insurance : You can protect your natural gas car with conventional motor insurance. Check in advance whether the insurer grants you an environmental bonus.

Advantages and disadvantages


Natural gas powered cars have advantages and disadvantages. As a consumer, you have to decide for yourself which advantages or disadvantages outweigh you.


  • Environmentally friendly: In operation, natural gas vehicles emit significantly less CO2 than cars with diesel or gasoline engines. The savings are up to 25 percent. Hydrocarbons are emitted over 30 percent less and nitrogen oxides up to 95 percent less.
  • Cheap fuel: Since natural gas (GNG) is still subsidized, the fuel costs are significantly lower compared to diesel or gasoline.
  • More efficient: Natural gas-powered engines are said to be up to ten percent more efficient than gasoline engines.
  • Less fuel transport: Natural gas filling stations usually do not need to be supplied via tank trucks. This eliminates truck transport on the roads and less polluting the environment.
  • Funding options: Car drivers can use the funding opportunities provided by gas suppliers when purchasing them.


  • Infrastructure: In Germany, the gas station network for natural gas is not expanded nationwide. Natural gas is available at just under 1,000 gas stations. Below that the range can suffer. This is especially true when traveling abroad.
  • Lower model selection: Not every manufacturer offers a natural gas powered model. Thus, the selection for corresponding vehicles is rather low.
  • High tank volume: Due to the larger volume of the natural gas tank, the loading area can be reduced.
  • Higher acquisition costs: Natural gas cars are up to 4,000 euros more expensive than conventionally powered cars. A conversion to natural gas can cost up to 5,000 euros.