During the last decade, alternative fuels have had a larger diffusion, especially in niche applications. Recent European energy policy has promoted the diffusion of renewable energy sources to reduce greenhouse gases (GHG) from fossil fuels. In this context also biofuels production has increased.
The problems of land use competition with primary human needs, connected to the first generation biofuels , will be reduced by the second generation biofuels. In fact they allow efficient production processes to convert biomass from not-food crops. Further improvement are expected from the assessment of the third generation biofuels obtained with low energy input, and with high yield, from marginal or unproductive land.
Also fossil sources could be used to produce reformulated fuels for transports. The second generation technology itself could be used to convert natural gas in hydrogen or GTL (Gas to Liquid, used in compression ignition engines) or, to convert coal in SNG or H2, or CTL (Coal to Liquid, also used in diesel engines). In both cases (production of liquid or gaseous fuels for transport), with fossil sources as feedstocks, not necessarily a better well to wheel GHG emission could be achieved, as from biomass feedstocks.
Gaseous fuels, (LPG, CNG and hydrogen, when available from an energetically convenient point of view) can reduce pollutant emissions at the exhaust of engines. Anyway the problems in supplying and storing hydrogen on board vehicles must be taken in account, because of its density, about one order of magnitude lower than NG, implying an appreciable autonomy range reduction.
Therefore CNG and hydrogen, or their blends, can be used successfully in “closed” vehicle parks in urban areas (public transport, distribution of goods, waste collection).
In Istituto Motori research activities are actually in progress for:
- Biodiesel and bioethanol, particularly in blends with diesel oil and gasoline;
- Natural gas and H2 blends;
- Liquid natural gas (LNG)