The Ship Energy Efficiency Management Plan is a special tool devised by the International Maritime Organization (IMO) to measure and control the green house gas (GHG) emissions from ships. The main aim of SEEMP is to not only reduce harmful emissions from ships but also to improve efficiency and decrease fuel consumption. Mostly all new ships are implemented with SEEMP and EEDI tools to keep a proper check on pollution from ships.
However, according to Chief Engineer Mahendra Singh, managing ship’s energy efficiency has lot to do with the habits of the crew members than the plans made on paper. In fact, according to him, the ship energy efficiency management plan should be termed as ship energy efficiency improvement habits.
Just like in every field, habits and attitude are the most important things on board ships. If you spend a lot of time in planning but don’t implement it seriously then the efforts are of no use.
The biggest saving in fuel consumption, as important aspect of SEEMP, is achieved by reducing speed of the ship suitably while negotiating rough weather. Many times, engine room officers are mistakenly driven by an Estimated Time of Arrival – ETA ( many mishaps have happened due to this alone) and simply to follow it rigidly they do not reduce speed even if it puts major stain on the engine and the ship’s structure.
For the new ships and the ships which will come in future, there are going to be lot of advanced features implemented, concerning the hull shape and improved paints and various other techniques for wake equalization and flow separation, however for existing and older vessels below mentioned points should be noted for ensuring ship energy efficiency improvement.
1. Energy Power Management: Generators should be run on as high load as possible if burning heavy fuel. The engineers should ensure that when the ship is out at sea, the running generator must take the maximum load. For this, all the generators are to be maintained in good condition or else for a normal sea load, if two generators are running together even when only one can take the load, the overall fuel consumption and engine emission will increase.
2.Understanding the importance of Stoichiometric ratio: Air and Fuel are the things that marine engineers need to manage but it is easier said than done. In order to judge if an air-fuel mixture has the correct ratio of air to fuel, the stoichiometric air fuel ratio has to be known. If the composition of a fuel is known, this ratio can be calculated rather easily.
3. Maintenance of fuel injectors and fuel pumps and ensuring correct fuel viscosity at the injector must be of high priority.
4. Maintaining the scavenge pressure by regular cleaning of Turbochargers and the Air coolers is also important.
(An important question that needs to be answered here is – who will do it? We are mostly used to working with the fitters but on many ships there is only one fitter and a tug of war always exist between the engine and deck department to utilize the fitter. The answer to this question is known to all but spoken by none.)
5. Ballasting and De-ballasting should, as far as possible, be done by gravity. How much quantum of ballast we should carry and where (in which tanks) is an art and this will depend upon our route. Some officers insist on emptying all ballast by pump and fill up again by pump with total disregard to stress and strain on the steel structure. With all due respects to deck department, it is observed that not many officers have adequate structural knowledge. Again, we need to think radically, why we cannot provide on the spot training during dry docking where we have great chance of seeing many things, not visible while afloat and in trade.
Checkout our ebook : A Guide to Drydocking of ships for engine room department
6. Cleaning of smoke sides of oil fired boiler and the economizer should be given importance and boiler pressure is to be adjusted depending upon the needs (trading in cold area or hot area). In hot areas there is no need to open steam to all bunker tanks but we often do not clean the dump condenser nor maintain dumping valve on auto. Moreover, to cope with the boiler pressure, officers end up opening steam full in all tanks. These are important things and the Class surveyors, while surveying the boiler, should pay attention to these important accessories, which are mostly the main causes of commotion in the Engine room.
Read: Energy audit of boilers
7. Viscotherm is not commonly checked during surveys of Class Societies; however, it is an important equipment in connection with correct burning of fuel. Earlier, it was perhaps not considered necessary but with emphasis on clean exhaust and added attainment of Energy efficiency, this equipment attracts attention.
8. Container ships sometimes attain up to 22-24 Knot speed burning lot of costly fuel. This can be justified if the aim is to catch a convoy but not for a normal run when in many cases such a gain will be nullified by delay in berthing, a slack customs clearance in ports and delays further down the multimodal system up to the door step. Slow-steaming, a concept universally adopted must be practiced. It will be worthwhile to give a thought; can we save some fuel by reducing a few notches.
9. De-rating of main engine: As mentioned in the above point of the advantage of fuel saving in slow steaming, the engineers have to consider the power rating of the engine before adopting this technique. “De-rating” of the main engine to the new speed and new power level (around 70%) involves the timing of fuel injection, adjusting exhaust valves, and exchanging other mechanical components in the engine.