CNG and CBG — together known in Sweden as fordonsgas (vehicle gas) — are among the most established alternatives to petrol and diesel. This page explains what the gases are, how gas vehicles work, and the role the fuel plays in the Swedish vehicle fleet.
What is CNG?
CNG stands for Compressed Natural Gas. It is a fossil gas whose main component is methane (CH₄) — the same molecule found in household gas. To fit enough energy into a vehicle tank, the gas is compressed to around 200 bar in composite or steel pressure vessels.
What is CBG?
CBG stands for Compressed Biogas. Biogas is produced when organic material is digested without oxygen — for example sewage sludge, food waste, or residues from farming and the food industry. The raw gas is cleaned and upgraded to vehicle quality, which means a methane content of around 97 %.
Chemically, CBG is identical to CNG — it is exactly the same methane molecule. A vehicle cannot tell them apart, and both can be filled in the same vehicles at the same stations. The difference is the origin: CBG is renewable and circular, CNG is fossil.
Vehicle gas in Sweden
In Sweden, CNG and CBG are usually sold together as vehicle gas (fordonsgas), sometimes blended in the same tank. Sweden has long been at the forefront internationally: a large majority of the vehicle gas sold in the country is biogas, giving the fuel a considerably better climate profile than in most other countries.
Vehicle gas is bought and measured in kilograms rather than liters. As a rule of thumb, 1 kg of vehicle gas corresponds to roughly 1.5 liters of petrol in energy content — which is why gas consumption is stated in kg/100km while petrol cars use l/100km. It is also why the price per kilogram cannot be compared directly with the price per liter: the cost calculator converts it for you.
Vehicles and filling up
- Passenger cars running on gas are usually so-called bi-fuel cars: they carry both a gas tank and a petrol tank, and automatically continue on petrol when the gas runs out. The gas range covers normal commuting, with the petrol tank as backup.
- Heavy vehicles — city buses, distribution trucks, waste collectors and taxis — are often dedicated gas vehicles with engines designed for methane from Scania and Volvo.
- Filling up is similar to conventional refuelling: the gas is stored in a pressure dispenser, the nozzle locks onto the connector, and filling takes a few minutes. You pay per kilogram.
The network of filling stations has grown up around larger cities and key transport corridors, with the best coverage in southern and western Sweden. The range of new gas passenger car models has shrunk as electric vehicles have expanded, but demand for gas remains strong in heavy transport and in vehicles covering many kilometres per year.
Climate and environment
- CBG from waste and residues is circular and, in a life-cycle perspective, close to climate-neutral operation — the carbon released when the gas is burned is already part of the natural cycle.
- CNG produces roughly a quarter lower carbon dioxide emissions than petrol when burned.
- Gas driving produces lower nitrogen oxide and particulate emissions than diesel, improving air quality in cities — one reason many cities have invested in gas buses.
- Gas engines are also quieter than diesel engines.
One important caveat: methane is itself a potent greenhouse gas, so even small leaks in production and distribution affect the climate benefit. Requirements on tight systems and methane cleaning have therefore been tightened, and it is one reason why the traceability and origin of biogas matter.
Advantages and limitations
| Advantages | Limitations |
|---|---|
| Lower fuel cost than petrol and diesel | Fewer filling stations than petrol and diesel |
| High share of renewable biogas in Sweden | Shrinking range of new passenger car models |
| Lower nitrogen oxide and particulate emissions | The gas tank takes up boot space in cars |
| Works here and now for heavy transport | Shorter range per fill than diesel |
| Quieter engines | Prices vary between stations — compare first |
The road ahead
While electrification dominates passenger car development, vehicle gas is one of the most established renewable fuels for vehicles that are hard to electrify today — city buses, distribution vehicles, and heavy transport with high annual mileage. For long-haul heavy trucks there is also liquefied gas (LNG/LBG), which offers higher energy density but is a separate technology with its own stations.
Want to know what gas costs compared to petrol, diesel and electricity in your case? Try the cost calculator — it prefills the gas price with today's median from Gasjakten's price data. Current station prices are in the price list.
For further reading about vehicle gas in Sweden, we recommend the industry association Energigas Sverige (in Swedish).
