New report highlights vessel speed reduction benefits
12 November 2019 | Mitigation
Main engine power-demand can fall by 27% when a ship decreases its speed by 10%, according to a study commissioned by European Federation of Transport & Environment.
Undertaken by environmental sustainability experts, the new study, The multi-issue mitigation potential of reducing ship speeds, also notes that when a vessel takes longer to sail a given distance at a lesser speed, the energy required for the voyage can drop by 19%.
However, the report does note that other factors will also affect the relationship between ship speed and engine power — including weather conditions and, at a fleet level, the extra ships needed to provide the same transport work. Consequently, the fuel and carbon dioxide (CO2) emissions-reductions linked to slower vessel speeds will probably be lower than these headline figures.
The study references recent work by Faber et al. which estimated the CO2 emission-decrease potential for 10%, 20% and 30% speed-reductions, for the three large vessel types, from 2018 out to 2030.
While the specific level of emission-reduction was dependent upon ship type, the analysis indicated overall that baseline CO2 emissions could fall by about 13% and 24% if ships cut their speeds by 10% and 20% respectively.
In relation to sulphur oxide (SOx) and nitrogen oxides (NOx), the report says that a fleetwide vessel speed-decrease of 10% to 20% was assumed to cause a decline in fuel consumption and NOx and SOx emissions of about 13% and 24% respectively.
The report comes on the eve of the latest round of United Nations vessel climate negotiations at the International Maritime Organization (IMO).
‘Speed-reduction is the closest thing to a silver bullet the IMO will ever see,’ John Maggs said.
‘Delegates attending this week’s IMO climate negotiations have on the table proposals to reduce ship speed that would not just make a big dent in shipping’s climate impact but would massively reduce air pollution, underwater noise pollution and the incidence of fatal collisions between whales and ships, all issues that the IMO must also deal with.’