school energy&environment

The transport

Oil is present in sufficient quantities to start production only in certain areas of the world, therefore most of it needs to be transported to reach refineries and the place of consumption. Italy, for example, imports 91.4% of the oil it consumes (Source: eni, World Oil & Gas Review 2014).
In terms of transport, there are two complementary ways to transport oil: pipelines and oil tankers. Pipelines include a system of 10-12 metre long steel pipes electrically welded together. They are generally buried at a depth of 3-15 metres or positioned on the sea bottom. The flow of crude oil along the pipeline is ensured by large pumps distributed along the route at distances ranging from 50 to 250 km according to the characteristics of the territory to be crossed. Control and safety stations distributed along the route ensure transportation to ports and refineries.
The oil transportation stage is particularly delicate by sea, since it can turn into one of the main pollution sources of seas and oceans if shipwrecks occur.
A modern tanker is equipped with separate double hull storage compartments (i.e. equipped with a double metal shell to protect the oil being transported) and other complex failure prevention systems to minimize the risk of oil spills in the sea. Before the oil crisis in the 1970s, oil tankers were huge (450 m long, 500 tonnes of tonnage), but this trend was changed by the re-opening of the Suez canal (which called for smaller ships crossing it), the changed market conditions and, during the last years, environment preservation and safety considerations. To reduce the environmental impact of those ships, new tank cleaning systems were introduced which allow the collection of the oil residues to be treated in plants on the mainland instead of discharging them into the sea.