Around the world, research teams from the automotive, oil and chemical industries are working intensively on the development and production of alternative fuels (including fossil fuels) as well as fuels from renewable and almost inexhaustible resources.
Mercedes-Benz is committed to using the cleanest possible fuels in order to offer its customers vehicles featuring the latest technology and the lowest possible emissions. Further optimisation of fuel consumption and emissions is possible only in combination with optimised fuels.
Natural gas is one of the alternative fuels. Its principal constituent is methane (CH4) and it has the lowest carbon content (which is converted to CO2 during combustion) of all fossil fuels. Its emissions of oxides of nitrogen (NOx), soot and reactive hydrocarbons are also lower than those of liquid fossil fuels. One kilogram of natural gas – it is carried in pressurised tanks and is therefore also known as compressed natural gas (CNG) – has an energy content equivalent to that of 1.5 litres of petrol. Operating costs which are some 50 percent lower are another welcome benefit of natural gas.
Liquefied petroleum gas (LPG) is an alternative to natural gas. The basic gases are propane and butane or mixtures of the two which are liquefied by means of a slight (2 to 8 bar) increase in atmospheric pressure. High energy density, residue-free combustion, environmental compatibility and the high product purity (there is no sulphur or lead content) make LPG a clean and cost-effective fuel.
"Gas to liquid"(GTL) fuels are gas-based, synthetic liquid fuels which are referred to collectively as SynFuel® products. Produced from natural gas in a two-stage process, they most commonly take the form of petrol and diesel. The benefits of SynFuel® products are the lower overall emissions, a factor which is noticeable in the case of both modern and, above all, older engines, and the fact that these are achieved without the need for any engine modifications whatsoever.
Renewable fuels are biomass to liquid (BTL) fuels from CO2-neutral biomass, a sustainable resource which grows continuously through the interaction of CO2, water, plant nutrients and sunlight while also producing oxygen which is essential for life. Man's use of biomass, be it for food, heating, electricity generation or as fuel, is compatible with the natural biomass cycle which has no impact on the Earth's climate.
SunDiesel, the diesel fuel based on biomass, is produced by Choren Industrie in Freiberg (Saxony). Mercedes-Benz and Volkswagen have been cooperating on the development of this fuel since 2002. The SunDiesel production process, which uses a new technology for the thermal gasification of solid biomass, is currently the best way – in terms of both ecological and economic considerations – of transforming biomass into energy.
Biodiesel is obtained exclusively from a specific part of the plant rather than from the entire crop. Furthermore, the aggressive chemical properties of biodiesel mean that it is necessary for the engine and fuel tank to be modified. The best-known variety of biodiesel is based on rape seed oil, which is marketed in standardised form as rape seed oil methyl ester (RME).
Hydrogen is potentially the ideal vehicle fuel. It combusts completely in combination with oxygen, emitting nothing but pure water vapour. Hydrogen is easy to transport and its storage has no environmental impact. As a secondary energy medium, it is still obtained from a primary energy source – natural gas – today. The prospects for obtaining hydrogen from biomass are very promising. Hydrogen-powered vehicles require their own network of filling stations for a reliable supply of the fuel.
Methanol is a hydrogen storage medium which can be produced from any source of carbon, such as sustainable organic raw materials or industrial waste gases. Today, methanol is obtained principally from natural gas which is available in large quantities around the world. Methanol can be transported, stored and handled in a similar way to petrol and diesel.
