In terms of the relation between the quantity of freight, distance covered and harmful emissions, however, ships remain the cleanest means of transport. Sea transport produces only 0.5 grams of nitric oxide emissions per ton and kilometre. Road freight produces 1.9 grams and air freight as much as 8.6 grams per ton. As around 80 per cent of the world’s freight transport is by sea, these differences are extremely important.

In terms of its CO2 emissions of just 10 to 15 grammes per laden tonne and kilometre travelled, a large container ship is hard to beat. Trucks generate between 51 and 91 grammes, while air transport generates between 673 and 867 grammes of the greenhouse gas.

Notwithstanding the huge efficiency of sea trade, our marine diesel engines are still being continuously developed. While for our large-bore two-stroke engines, it was crucial in recent years to be able to burn heavy oil of virtually any quality, cleaner natural gas has now been adapted as a fuel for the two-stroke sector, too. All MAN B&W two-stroke engines  satisfy the IMO's environmental regulations.

Our smaller four-stroke engines, which are used e.g. in high-speed ferries, naval ships or cruise ships, are also particularly efficient and low on emissions. As regards marine propulsion systems with medium-speed engines, we always take into account the whole propulsion package comprising main engine, gears, shaft and cp-propeller, which we offer from a single source. When these components are perfectly harmonised, this further boosts efficiency and therefore saves fuel.