RightShip’s GHG Rating has increased in prominence, and its uptake as a vessel selection tool for charterers has risen steadily over time. As a direct result of this, the application of energy saving equipment for the purpose of improving a vessel’s GHG Rating has also become more common.
The use of engine power limitations (EPLs) have also increased due to their perceived inexpensive installation costs relative to the benefit they have on the EVDI calculation and a vessel’s GHG Rating.
An EPL establishes a semi-permanent, overridable limit on a ship’s maximum power, and therefore its speed. For mechanically-controlled engines, this would take the form of a mechanical stop screw sealed by a wire that limits the amount of fuel that can enter an engine. For newer, electronically-controlled engines, an EPL would be applied via a password-protected software fuel limiter.
An EPL is overridable if a ship is operating under adverse weather conditions and requires extra engine power for safety reasons.
EPL acceptance criteria
Before accepting and applying the benefit of energy saving equipment to a vessel’s GHG Rating, RightShip require suitable documentation confirming installation and quantifying the improvement.
EPLs will only be accepted if they meet certain criteria, designed to ensure their application aligns with RightShip’s overarching aim of improving vessel efficiency and environmental sustainability. The documentation required for EPLs must demonstrate that the engine has been limited in a ‘semi-permanent’ manner.
1.One or more statements from class or another appropriate verifier confirming:
- Revised main engine MCR
- Date of EPL
- Presence of a surveyor to the EPL
- Assessment of minimum propulsion power (MEPC.1/Circ.850/Rev.2). Assessment level 1 – minimum power lines method only
- Addition of the EPL to class surveys for periodic review
- Revised EVDI, with calculation details (EVDI statement of fact or technical file)
2.EPL Management Plan
Documentation outlining the internal company processes to manage the EPL, to enable periodic reviews in class surveys. This includes:
- Internal company processes to manage and maintain the EPL. For example, some vessel owners have provided their new employee induction manual ‘On Boarding’ procedure or maintenance checklists containing reference to the EPL and how it should be maintained / managed etc.
- External periodic review of the EPL. This usually takes the form of a statement from class confirming that the EPL will be inspected in the annual class survey or inclusion of the EPL on class survey list.
Limitations to EPL acceptance
- A vessel must not limit their engine below the IMO’s minimum propulsion power guidelines: Assessment level 1 – minimum power lines assessment (MEPC.1/Circ.850/Rev.2). Note: Assessment level 2 – simplified assessment is not acceptable
- RightShip will only accept one EPL per vessel. I.e. a vessel cannot undertake more than one EPL
- The required documentation, as outlined above, must be provided before any benefit will be applied to the vessel’s GHG Rating.
Rationale for acceptance criteria
The EPL acceptance criteria are designed to maximise the integrity of EPL application and to provide a ‘level playing field’ for operators looking to improve vessel efficiency. The rationale behind the acceptance criteria for EPLs has been outlined below.
- There has been a significant increase in EPL applications, which have greatly impacted the peer groups and dynamic nature of the rating in certain segments.
- The impact an EPL has on a vessel’s GHG Rating is arguably larger than the realised impact it has on emissions reduction. 
- The above may detract from the investment in, and development of, other energy saving equipment that potentially have greater impact on emissions reduction
- As the application of an EPL can be reversed without the need for a dry docking, ensuring that the EPL remains intact in non-emergency scenarios is vital.