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Friday, May 3, 2019  (Comments: 2)

New proposals to limit the speed of ships as a way of reducing carbon emissions will have the opposite effect, the UK Chamber of Shipping has reiterated.

The proposals by the French and Greek authorities will be discussed at a meeting of the IMO (MEPC74, 13-17 May), and call on regulators to enforce a speed limit on international shipping – despite there being no evidence that such limits will result in lower carbon emissions.

Anna Ziou, Policy Director at the UK Chamber of Shipping repeated the Chamber's warning: “The shipping industry is committed to reducing its carbon emissions by at least 50%.  To achieve this we need continued investment in green technologies that will allow ships to conduct their business through a range of low carbon fuels such as battery power, hydrogen fuel cells or even wind power.

“Shipowners have already limited their speed by a considerable amount in the past decade and whilst these proposals have good intentions, promoting further slow-steaming as a low carbon alternative for international shipping is just not good enough.  They will give a false impression that the industry is taking action, when in reality they will deliver no meaningful reduction in emissions.

“The scale of ambition required for the industry to meet the 50% target should not be underestimated so those companies developing and installing low carbon technologies should not be penalised for their investment.  These proposals will do exactly that, and suggest the problem will simply go away if we just drive ships more slowly. This could result in less research and development, and discourage meaningful attempts at eliminating carbon emissions.”

Ziou added that the proposals would lead to behavioural change in the wider supply chain that could further drive up emissions. “Speed reduction could result in supply chains using alternative modes of transport, such as road haulage.  This would increase overall emissions. In addition, ships may call at certain ports that are tidally constrained where a delay of just one hour could result in a knock-on delay of 12 hours to the vessel as it awaits the next tide.  Aside from the economic harm, this would unnecessarily create further emissions during the additional waiting time.”

Reader Comments (2)

If fuel consumption is proportional to the cube of the speed, then a reduction from 20.6 kts to 16.0 kts cuts consumption to less than half of the original per hour, while time at sea is increased 1.3 times. Fuel used per journey at 16 kts is therefore around 60% of that consumed at 20.6 kts. This looks like a 'meaningful' saving in emissions here and now. When, in due course, the boffins have developed carbon-free propulsion systems, then we can avail of them, but in the meantime, there's nothing false or miksleading about the reduced emissions.

By Bob Rees on Monday, May 6, 2019

If we assume that total volume of cargo to be shipped is fixed or increasing . Then if you slow a vessel down it will not be able to transport the same amount of cargo in a given any time frame, say 12 months. So additional tonnage is required to make up this shortfall in tonnage shipped . Therefore you would also need to take into consideration the emissions from the additional vessels required to carry the cargo that would not carried in a given time period on a vessel at reduced speed.

By Graham Carroll on Monday, May 6, 2019

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