Fuels in Transportation - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 29

the same engines as commercial petrol and diesel fuels. The combination of
individual fuels is possible.
CNG is only a small portion of the fuel used in road transport and its share is
growing very slowly. The use of LNG and hydrogen in road transportation as fuel
is not yet sure.
2.5.2 Fuels in Aviation
The most important fuel in civil aviation is kerosene. The use of synthetic and
biogenic fuels in experimental airplanes is only a small portion of the complete
structure. Widespread substitution of kerosene with both new types of fuel is not
expected in the near future.
The industry aims to develop and to produce several fuel types as uniformly as
possible and to make it easy to switch between fossil and synthetic or biogenic
fuels. Theoretically, the first step of adding 50% biogenic and synthetic fuel can be
increased to 100%, because chemical additives make alternative fuels very similar
to classic kerosene. However, the introduction of alternative fuels will take a long
time to happen.
The combustion of hydrogen results in 2.6 times more water vapor than the
combustion of jet fuel and would completely eliminate CO 2 emissions in aviation.
Beside technological diffculties, a disadvantageous aspect is that the utilization of
hydrogen requires a new system of logistics, storage, and handling for all aircraft
and ground equipment.
2.5.3 Fuels in Maritime Shipping
The most common fuels in ships are MDF and Heavy Fuel Oils. These are con-
ventional fuels and available at a low cost worldwide. Marine diesel engines could
theoretically use a broad range of synthetic and biogenic fuels and their mixtures,
i.e., flended fuels if engines and containers of the ships were modified.
The application of synthetic and biogenic fuels is not permitted in shipping since
their energy content is too low to guarantee the average needed distances at sea,
except special sea-going and inland ships. Moreover, the costs of first- and second-
generation biogenic fuels are much higher than the cost of fossil marine fuels. It is
expected that the next generations of biogenic fuel will achieve more advantages in
marine transport. Despite all positive developing results, the introduction of bio-
logic and synthetic fuels in ships will happen slowly and will be evolutionary.
LNG is used in LNG carrying tankers, and hydrogen in the fuel cells of
submarines. The proportion of non-fossil fuels used in the ship transportation is
very small. The first broad ranged applications are expected in ferries, inland ships,
and special purpose vessels.