Operation of Auxiliary Machinery
The ship’s diesel generators operate in port in order to produce electricity for operation of a large number of machinery and systems in engine room, deck and accommodation areas. Amongst them are the engine room auxiliary machinery like fans, pumps and other devices. On the accommodation side, the need for lighting, HVAC and galleys exists in port. In order to save energy and reduce emissions, auxiliary machinery utilisation in port should be minimized with consideration for safety.
There are practical evidences showing that such machinery are normally over-utilized in ports. Ship staff may follow the same processes as sea-going condition and keep the machinery running in the same way as during sea going conditions. This could also be considered as a way of avoiding additional processes, remain ready to leave the port without the need to re-start some of the machinery and for simple reasons that the company may not have plans and procedures on how the port operations with regard to machinery utilization need to be handled.
This should not be the case and it can be changed via specific planning for the engine room machinery operations for at-berth/at-anchor operation to ensure energy efficiency while safety is taken into account. The main aim of the plan will be to save energy via switching off the unnecessary machinery. As examples, the following may be undertaken:
- Minimizing the number of running auxiliary machinery based on port operation requirements. There are a large number of pumps on board such as sea water cooling pumps, steering pumps, engine water circulating pumps, engine lubricating oil pumps, etc. All these need to be investigated and a plan for their port-operation should be devised based on port requirements.
- Minimizing the number of A/C units operated or switch them off when conditions permit. The mean temperature on board does not need to be lower than 24ºC degrees.
- The number of engine ventilation fans should be reduced in port or brought to slower speed. Since main engine(s) is not working in ports, there is no need to run all the engine room ventilation fans.
- The fuel treatment machinery need to be reviewed if they all needed to run in the same way as sea-going condition in view of the significant reduction of ship fuel consumption because of main engine being switched off.
- Minimization of use of compressed air and its use where required. Compressed air is an expensive commodity and for example should not be used for ventilation purposes.
As indicated, these measures will provide less demand for electric generation and thus will lead to reduced fuel consumption. Additionally, the machinery run hours will reduce and this will be beneficial from maintenance point of view.
There are opportunities for reduction of energy needed in the accommodation area when in port. Although these measures are applicable to sea going conditions as well, it will be more effective under port condition. Some aspects include:
- Lighting system: The lights in spaces when not in use can be switched off and deck lighting during day hours can be avoided.
- Galleys: The galley area also provides some opportunities. For example, lighting and electric equipment can be switched off after use.
- Deck lighting: No need for lighting during day time.
These measures also help to reduce demand for electric power (MariEMS 2017).