EEDI Methodology for the Ro-Ro Sector: A Positive Outcome

EEDI has (officially) entered our shipping lives: major ship types (tankers, bulk carriers, containerships etc) contracted after 1 January 2013 will need to comply with the new requirement.

2014.03.24 - EEDI Methodology for the Ro-Ro Sector A Positive Outcome

The current EEDI framework is very much a ‘one size fits all’ approach, where most ship types are treated on the basis of three main parameters:

  • Design (or reference) speed
  • Main engine installed power
  • Deadweight tonnage (DWT).

Everything else in the long EEDI equation is secondary – if the three base ingredients do not work together then you risk ending up with an EEDI figure which has little bearing on the ship’s energy efficiency.

This is why ro-ro passenger and ro-ro cargo ships have been, so far, left outside the current EEDI framework. It was acknowledged that the EEDI in its standard form could not cope with the design and operational diversity of ships engaged in short-sea shipping. Examples of this include:

  • Day ferries vs. night ferries.
  • Passenger cabins vs. total lane length.
  • Ships size in relation to specific ports / waterways / locks etc.
  • Redundancy requirements and safe return to port.
  • Operational requirements (speed, manoeuvrability).

The same can be said for other smaller and specialised ship segments currently outside the EEDI framework and the Deltamarin study for EMSA does a very good job at summarising the technical challenges.

It is therefore great news that at the recent IMO MEPC 64, a consensus on the way forward has been achieved.

The solution is based on the existing EEDI methodology but takes into account non-dimensional parameters such as the Froude number, length/beam, beam/draught and DWT/GT ratios to address the design diversities of these ships. Details are being fine-tuned and a solution is expected to be finalised at MEPC 65 (May 2013).

This means that energy efficiency of ro-ro passenger and ro-ro cargo ships can be addressed without compromising safety and operational requirements.

It is without doubt a positive outcome showing that industry collaboration and combined technical expertise can overcome the shortfalls of the EEDI mechanism. As it is often the case, technical obstacles are a lot easier to conquer than political ones.

The article was initially published in Lloyd’s Register Blog. Lloyd’s Register provides professional services across the life cycle of assets that are of critical importance. Set up in 1760 to survey merchant ships, and ‘classify’ them according to their condition, in the 1900s Lloyd’s Register began to apply expertise to other sectors. Lloyd’s Register now offers services to the marine, energy and rail industries, and management systems services across a wide range of sectors, focused on improving safety, quality and performance.


Author - Dimitris Argyros, Lloyds Register Dimitris Argyros is a Lead Environmental Specialist in the Marine Product Development Department, with background in Naval Architecture and Marine Engineering. He is particularly involved in the areas of exhaust gas emissions and energy efficiency and has been closely following the developments at both regulatory and commercial level, especially in the area of EEDI. This involves participating at IMO with national delegations, being a member of the IACS working group focusing on the EEDI and also working closely with industry associations such as the Cruise Line Industry Association (CLIA) in developing the EEDI framework for vessels with non-conventional propulsion.

Leave a Comment

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: