The current MARPOL rules apply to all engines larger than 130 kW which are installed or modified after January 1, 2000. The limit for a two-stroke, slow moving marine diesel engine (rpm lower than 130) is 17g/kWh. New IMO regulations have been published which covers newbuildings
- from January 1, 2011 – max 14.4 g/kWh
- from January 1, 2016 – max 3.4 g/kWh
There is also a part covering vessels built between 1990 and 2000; if the manufacturer offers a kit to reduce emissions to 17 g/kWh it must be fitted at the first renewal survey one year after such equipment has been approved.
New international legislation for shipping, under the guidance of the International Maritime Organisation (IMO) takes a long time to be formulated. For example, discussions as to whether air pollutants should be included in the MARPOL regulations took place as far back as 1973. The decision then was to exclude them. In 1988, the issue came up again with another proposal being made in 1991. This was adopted in September 1997. Following a ratification process, the new regulations finally came into force in May 2005. During the 14 years between the initial proposal, and it actually taking effect, a great deal happened in terms of equipment being developed and as a result the finally approved regulations were completely ineffective.
