The report also describes how the so-called CO2 index may contribute to a reduction in CO2 emissions from the shipping industry in the future.

In recent years the international focus on CO2 emissions from the shipping industry has gained momentum. The Danish Shipowners’ Association thus wanted to gain a total overview of the historic development from 1912, when the first ocean-going diesel driven vessel was taken into operation, to the present-day to see whether the marine industry has become more energy-efficient.

Optimisation of fuel consumption
The report suggests that a so-called CO2 index can be issued, indicating a vessel’s CO2 emission per tonne of cargo per kilometre run. The index can be refined by a number of measures reducing the vessel’s resistance and improving the propulsion efficiency, e.g. by using new types of hull paint and improved propellers. A reduction in speed combined with increased size of the vessels also results in an improved CO2 index and this interaction is exactly what the report identifies.

Drop in CO2 as a result of economies of scale
The main author of the report, Hans Otto Kristensen of FORCE Technology, says: “The studies show that there has been a drop in CO2 emissions per transport unit from international shipping over the years, as the vessels have become better at making use of the fuel by applying more energy-efficient diesel engines. However, I can also conclude that the drop in CO2 emissions is primarily the result of economies of scale as the vessels – especially container vessels built in the last 30 years – have grown bigger and bigger”.

“However, comparing smaller types of vessels before and now, only a minor reduction of the exhaust emissions has been achieved within the last 95 years. The situation is more or less status quo where a drop might have been expected,” concludes Hans Otto Kristensen.

For debate
The report is meant as an active contribution to stimulate the debate which has been going on in recent years within the UN’s International Maritime Organisation (IMO) to improve and thus reduce the  environmentally damaging exhaust gas emissions, including CO2, which has an immense impact on global warming.

Read the full report.