Produzione e distribuzione di elettricità e calore
Maritime Transport Carriers
Autors: Alessandro Ruvio, Andrea Vicenzutti, Silvia Orchi
Production and Distribution of Electricity and Heat
In the maritime transport carriers’ sector, various technologies coexist for the production of energy for both propulsion and other on-board needs. The configuration of the electrical and propulsion system depends on the purpose of the ship, with significant variations between ships dedicated to different applications. At the propulsion system level, the ships are: mechanical propelled (internal combustion engines drive the propellers), electric propelled (electric motors drive the propellers), hybrid propelled (both types of engines drive the propellers, either together or separately, depending on the ship purpose). The onboard internal combustion engines are Diesel cycle ones (2 and 4 stroke) fueled with heavy oil fractions, and are used for both the mechanical propulsion and electrical generation. At the mooring, with both ship and port equipped, it is possible to use the so-called shore connection to power the onboard electrical loads the ground, and switch off the ship motors. Following the entry into force of emission regulations in the maritime transport sector, various technologies for reducing the environmental impact of ships have been (and are currently being developed) developed. Existing solutions include scrubbers and catalytic converters in the exhaust system, use of low-sulfur fuels and/or natural gas. Regarding medium and long-term solutions, several proposals at different levels of technological and commercial maturity are present. These include the energy storage systems integration, fuel cells, exploitation of solar or wind energy, use of synthetic fuels and biofuels. It is also worth mentioning maintenance, management and technical solutions, such as the engines incremental improvement, adoption of electronic drives for onboard fans and pumps, waste heat recovery, hydrodynamic improvements to propellers and hull, and reduction of navigation speed. Given the extreme variability of the ships’ types and routes, it is impossible to define a single optimal solution, but it is necessary to develop ad hoc solutions for each ship. It should be noted that currently the percentage of ships with technological solutions that are not based on internal combustion engines fueled by heavy oils is negligible, even if the share will grow in the future given the age of the actual fleet (in regards to a 30 years life expectation) and the policies to reduce pollutant emissions promoted worldwide. Given the peculiarities of maritime transport, it is difficult to clearly distinguish the international market from the national one, also given the specificity of Italy in terms of orography and position in the Mediterranean. International maritime transport is a crucial sector for Europe, covering 75% of extra-EU trade and 36% of internal trade, and is critical for the entire logistics chain in the sector. Still very dependent on fossil fuels, maritime transport is one of the most efficient modes of transport, with significant potential for improvement. The latter can be implemented with various measures, each with a different degree of complexity and economic burden. Europe also has an important tradition in shipbuilding and related instrumentation, although a certain contraction has been observed in recent years due to the relocation of shipyards to China, Korea and Japan. Passenger traffic in European ports counts 400 million embarkations/disembarkations and about 119 million TEU, equal to 16% of world container traffic.