Compressed natural gas in the context of "Diesel fuel"

A filling station (also known as a gas station [US] or petrol station [UK/AU]) is a facility that sells fuel and engine lubricants for motor vehicles. It serves as a local fuel depot and retailer who receive fuel products from refineries (via regular tank truck resupplies), keep the fuels in (typically underground) storage tanks, and distribute individual product to motorist consumers at a daily varied price.

The most common fuels sold are motor fuels such as gasoline (a.k.a. petrol, often as multiple products according to different octane ratings) and diesel fuel, as well as liquified petroleum gas (LPG, i.e. autogas), compressed natural gas, compressed hydrogen, hydrogen compressed natural gas, liquid hydrogen, kerosene, alcohol fuels (like methanol, ethanol, butanol, and propanol), biofuels (like straight vegetable oil and biodiesel), or other types of alternative fuels. Fuel dispensers are used to pump fuel into the fuel tanks within vehicles, gauge the volume of fuel transferred to the vehicle, and calculate the financial cost the consumer must pay. Besides fuel pumps, another significant device found in filling stations and capable of refueling certain (compressed-air) vehicles is an air compressor. However, these are generally used to inflate car tires.

A motor fuel is a fuel that is used to provide power to the engine (motor) of vehicles — typically a heat engine that produces thermal energy via oxidative combustion of liquid or gaseous fuel and then converts the heat into mechanical energy through reciprocating pistons or gas turbines.

Currently, the majority of motor vehicles, powerboats and light aircraft worldwide are propelled by internal combustion engines powered by petroleum-based hydrocarbon fossil fuels such as gasoline, diesel or autogas, while larger ships and aircraft use marine diesel oil and kerosene to power gas/steam turbine, turboprop and jet engines. Other fuel types include ethanol, biodiesel, biogasoline, propane, compressed natural gas (CNG) and hydrogen (either using fuel cells or hydrogen combustion). There are also cars that use a hybrid drivetrain of different power sources. The use of synthetic alternative fuels (especially renewable biofuels) is increasing, especially in Europe, as well as increasing mass adoption of battery electric vehicles (which are powered by battery-stored electricity instead of fuels).

HCNG or H2CNG (hydrogen compressed natural gas) is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances.

(regarding the acronyms in the above emissions chart:

Alternative fuels, also known as non-conventional and advanced fuels, are fuels derived from sources other than petroleum. Alternative fuels include gaseous fossil fuels like propane, natural gas, methane, and ammonia; biofuels like biodiesel, bioalcohol, and refuse-derived fuel; and other renewable fuels like hydrogen and electricity.

These fuels are intended to substitute for more carbon intensive energy sources like gasoline and diesel in transportation and can help to contribute to decarbonization and reductions in pollution. Alternative fuel is also shown to reduce non-carbon emissions such as the release of nitric oxide and nitrogen dioxide, as well as sulfur dioxide and other harmful gases in the exhaust. This is especially important in industries such as mining, where toxic gases can accumulate more easily.

Biogas is a gaseous renewable energy source produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, wastewater, and food waste. Biogas is produced by anaerobic digestion with anaerobic organisms or methanogens inside an anaerobic digester, biodigester or a bioreactor. The gas composition is primarily methane (CH
₄) and carbon dioxide (CO
₂) and may have small amounts of hydrogen sulfide (H
₂S), moisture and siloxanes. The methane can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used in fuel cells and for heating purposes, such as in cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.

Biogas can be upgraded to natural gas quality specifications by stripping carbon dioxide and other contaminants. Biogas that has been upgraded to interchangeability with natural gas is called Renewable Natural Gas (RNG). RNG can be used a drop-in fuel in the gas grid or to produce compressed natural gas as a vehicle fuel.

Bi-fuel vehicles are vehicles with multifuel engines capable of running on two fuels. The two fuels are stored in separate tanks and the engine runs on one fuel at a time. On internal combustion engines, a bi-fuel engine typically burns gasoline and a volatile alternate fuel such as natural gas (CNG), LPG, or hydrogen. Bi-fuel vehicles switch between gasoline and the other fuel, manually or automatically. A related concept is the dual-fuel vehicle which must burn both fuels in combination. Diesel engines converted to use gaseous fuels fall into this class due to the different ignition system.

The most common technology and alternate fuel available in the market for bi-fuel gasoline cars is Autogas (LPG), followed by natural gas (CNG), and it is used mainly in Europe. Poland, the Netherlands, and the Baltic states have many cars running with LPG. Italy currently has the largest number of CNG vehicles, followed by Sweden. They are also used in South America, where these vehicles are mainly used as taxicabs in main cities of Brazil and Argentina. Normally, standard gasoline vehicles are retrofitted in specialized shops, which install the gas cylinder in the trunk and the LPG or CNG injection system and electronics. The conversion is possible because the gases can use the spark ignition of a gasoline engine.