Public Road Transport

Transport technologies

The public road transport sector is, at present, strongly affected by the effort being made at international level to boost the decarbonisation of road transport, which is responsible for 28% of gaseous CO2 emissions from energy end uses, with a continuous increase since 1990 ((EEA), 2018), despite the efforts made to improve vehicle performance. Boosting the use of Renewable Energy Sources (RES) also in road transport, through the use of Green Hydrogen, electricity and biomethane, represents an important opportunity to reduce the environmental impacts of the whole transport sector, to improve the security of energy supply and to boost the economy. In urban areas, where the distance travelled is often short and the energy recovered through regenerative braking could be significant, the use of battery electric vehicles seems a very promising option among all. In particular, Public Road Transport would represent a "key" to introduce electric energy for automotive operation in urban areas. Indeed, the electrification of Public Transport may be even easier than it would be for private mobility, thanks to an easier organisation of charging activities due to a well planned operation of the vehicles, for which many examples of BEB use are emerging in many cities around the world.

At the moment, however, public road transport is mainly provided by internal combustion engine vehicles powered by diesel and, with lesser diffusion, by methane, mostly compressed. Other technologies, such as hybrid buses, battery-powered electric buses or hydrogen buses (using fuel cells), are emerging, with varying degrees of maturity, in interesting commercial or demonstration applications. Hybrid buses, equipped with an internal combustion engine and an electric drive powered by on-board accumulators that recover energy during braking, have been the most immediate alternative for improving the emissions and energy performance of public road transport, especially in urban areas, without substantial changes to the operating model or the need for new infrastructure; and indeed they have already been adopted by some major Italian local public transport (LPT) companies. In the last five years, however, the development of lithium batteries and the reduction in their cost have led to a move towards fully electrically driven buses, which are now beginning to represent a significant market reality. The electrification process is also facilitated by the rapid development of charging infrastructure. High energy density lithium batteries now offer sufficient running autonomy and have solved the problems of safety, life cycles and cost, and today there are about 600,000 fully electric buses in circulation in the world (mainly in China), i.e. 16% of the circulating fleet and it is expected that by 2030 the share of newly registered electric buses will reach about 70% of the total (Source: Cassa Depositi e Prestiti).

Other possible solutions are trolleybuses equipped with batteries to allow autonomous running for short distances and battery electric buses with high power (>150 kW) fast recharging during service are interesting solutions (although with different implementation and safety requirements). The use of hydrogen in public road transport has provided good results in 15-20% mixtures with methane to power spark ignition engines, while hydrogen fuel cell buses are still penalised by high costs and fuel supply requirements.

The national circulating fleet of buses for urban and regional transport is about 100,000 vehicles (2018), mainly fuelled by diesel and mostly Euro II and Euro III approved (71% for urban transport, even higher percentages for suburban transport), followed by methane (27% for urban transport). Electric buses are only 1%, for urban use, but recent studies ("Electrify 2030", research carried out by The European House - Ambrosetti on behalf of the Enel Foundation and Enel X) report analyses of the electrification potential in Italy for other types of electric vehicles, working out the scenarios shown in Table 1 for the year 2030. The accelerated scenario foresees a substantial growth of the circulating fleet of electric buses up to 10%; it should be noted that the study precedes the creation of the NextGenerationEU and the National Recovery and Resilience Plan, in which specific resources are foreseen precisely for the electrification of European and Italian public transport. It should also be noted that the national market sees a good presence of national operators, large companies (about 40%) and smaller companies, but only in the internal combustion engine bus sector, while, as regards electrically powered buses, foreign companies are massively present (China, Poland).

22-08-2022

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