Building and operating vessels in a fuel efficient manner is a prerequisite for succeeding in the present competitive market with its high fuel prices. DNV is here to assist, and offers a wide range of services to help yards and owners save fuel and comply with regulatory requirements. Below is a short summary of some of the advisory services offered. These services are built on DNV’s strong technological basis, particularly in the areas of:
• Energy Efficiency Services
• Ship Hydrodynamics and Stability
• Noise and Vibrations
• Ship Operations
• Rotating Machinery
• Ship Structures and Concepts
DNV can provide technical and operational expertise to save fuel on newbuildings, for example Hull optimisation, and EEDI calculations, and on existing ships, for example Trim Optimisation, Ship Energy Audits, SEEMP and Energy Efficiency management projects.
Hull optimisation
The hull shape is one of the most important factors determining a vessel’s fuel consumption. The objective is to reduce the hull’s overall resistance when operating at different speeds and drafts. DNV offers assistance to yards, owners and designers to:
• Establish an operational profile that determines the conditions for hull optimisation
• Calculate the hull resistance of an initial design with CFD
• Optimise the hull form by proposing and testing several variations of the forebody and aftbody lines
• Calculate an updated speed power curve
• Calculate the updated EEDI performance and advise on areas where the EEDI could be further improved
EEDI calculation
IMO has introduced new Energy Efficiency Design Index (EEDI) requirements that are applicable to all new vessels. DNV offers the following services:
• Gap Assessment: a review of all the design and sea trial documents required to calculate the EEDI as per IMO’s EEDI guidelines, including the identification of missing documents
• EEDI Calculation at the Design Stage: estimate the EEDI based on IMO’s guidelines
• EEDI Improvement: identify areas which could lead to a significant EEDI improvement with a minimum impact on the basic design
• EEDI Technical File: develop a technical document package to support the EEDI calculations and input data, ready for verification
Trim optimisation
Many vessels are not always operated at optimal trim, leading to increased resistance and fuel consumption. By using CFD, several loading conditions with different speeds and vessel drafts are analysed using operational data or the loading manual as a reference. Relevant trim levels need to be defined so that the ballast tanks can achieve such conditions.
The optimisation study will point out favourable trims for defined combinations of loading conditions and speeds. Optimising the trim by reducing the hull resistance may lead to a fuel saving of 1–5%.
Trim tables and an optional onboard decision-support tool are delivered by DNV to each vessel and are also applicable to sister vessels.
Ship Energy Audit
DNV offers to conduct Ship Energy Audits, either as a stand-alone service or as a supplement to the SEEMP or an energy efficiency project. In a Ship Energy Audit, a team of DNV’s machinery experts carry out an audit on board in order to:
• measure the efficiency of energy consumers on board
• interview ship staff with the objective of assessing the implementation of procedures and the general level of awareness related to energy efficiency
• witness the normal operation of the vessel during different modes and document the overall impressions during the voyage
SEEMP
IMO’s new requirements as to the Ship Energy Efficiency Management Plan (SEEMP) comes into force on 1 January 2013. DNV recommends companies to use this opportunity to create a momentum for reducing their fuel and operating costs.
DNV can also assist companies in preparing their SEEMP, either to get started or to prepare the plan itself. Key steps in this process are:
A. Information gathering, e.g. information on the current fuel consumption, operational profile and measures already undertaken on board
B. Interviews and a workshop focusing on improvement opportunities and future ambitions, as well as a ranking of these
C. Preparing the SEEMP
If done correctly, the SEEMP will not just ensure compliance but also lead to lower fuel consumption.
Energy Efficiency services
While the SEEMP is a simplified way to ensure fuel savings on board vessels, additional savings can be achieved through a more structured approach focusing on all areas, such as the voyage planning, bunker purchasing, hull cleaning, engine condition, strategy & plans, culture on board and performance management. This structured approach has been delivered through more than 50 Energy Efficiency projects for more than 1,000 vessels. DNV has extensive experience and can benchmark the performance against industry best practice.
Through the project, fuel saving initiatives will be quantified and prioritised. Of course, ultimate success lies in successful implementation on board, and DNV also assists in project management, solution development and implementation.
Source: DNV