Economic prosperity in the Western world has over the past century been built on inexpensive and abundant oil-based energy. Increasing demand and decreasing supply forces the oil price upwards. However, oil supplies will not expire all of a sudden and it will remain the dominant fuel in transports for decades to come.
The European Union has announced its ambition to reduce Europe’s dependency on fossil fuels. By 2010, 5.75 percent of diesel and petrol fuels used in the road transport sector should be substituted by biofuel. By 2020, biofuel, gas and hydrogen should represent 20 percent of the fuel used.
Biofuels
Scania believes that biofuels will make a valuable but limited contribution to the reduction of carbon dioxide emissions. Realistically, biofuels could account for about 10 percent of total fuel consumption in the transport sector by 2020. Due to limited availability of agricultural land, it cannot be produced in sufficient quantities to replace fossil fuel – only for mixing.
Efficiency is a main advantage of the diesel engine and this is not restricted to fossil diesel fuel. If mixed with biofuels in carefully controlled proportions, diesel fuel retains its favourable combustion properties and overall efficiency.
Scania diesel engines with unit injectors from the 4-series and onward may be run on 100 percent FAME fuel (e.g. RME), meeting European standard EN14214 or on a mix of 5 percent FAME in high-quality diesel.
Scania also markets diesel engines specially adapted to run on pure ethanol with 5 percent ignition improver.
Ethanol
Ethanol produced from sugar cane and other types of bio-mass is the biofuel that today has the biggest potential to reduce carbon dioxide emissions from transport. Ethanol is mainly used for passenger cars as low blend in petrol. However, it is also possible to fuel a diesel engine with pure ethanol if an ignition improver is added to the fuel. Scania has more than 15 years experience of this application and is the world’s largest manufacturer of ethanol-driven city buses.
Gas
In long-haulage, gas is not likely to be of great importance. The efficiency of a gas engine is inferior to that of a diesel. And the gas must be transported on the vehicle in bulky tanks that increase gross weight by some 500 kg and thereby reduce payload and cargo volume.
In the short and medium term, Scania views methane gas as a realistic alternative to diesel fuel in some inner-city operations. As regards noise, the gas engine is quieter and better adapted to urban operations than the diesel engine is. There is a slow growth in the demand for gas-powered vehicles in some countries. The methane gas alternative is closely interlinked with fuel taxation laws and the high cost of the distribution infrastructure.
Read more about gas-fuelled buses
Hydrogen
In a very long perspective a powertrain composed of a fuel cell and an electric motor might be an interesting alternative. A fuel cell fuelled by hydrogen has a reasonable efficiency also in heavy duty transport. But for the foreseeable future there are no methods to transport sufficient amounts of hydrogen gas on the vehicle. If hydrogen were transported in the form of methanol or another liquid fuel, the efficiency decreases, below that of a diesel. Furthermore, there must be a stable supply of hydrogen and the primary energy to produce it must come from a sustainable source.
To increase knowledge of environmentally compatible technology, Scania has taken part in a European project to develop a concept fuel cell bus. Read more
Synthetic diesel
Scania believes that synthetic diesel fuel – ideally suited to tomorrow’s high-efficiency diesel engines – can provide even better preconditions for clean combustion. It can be produced from various raw materials, for example biomass, waste and natural gas. In a future when hydrogen is produced in large quantities as an energy carrier, a synthetic liquid fuel carrying that energy and an internal combustion engine may prove to be the optimal solution.
