Energy savingS

There are many areas where reduced environmental impact and energy savings can be made on a vessel.

Engines and Propellers

Engines and Propellers

  • By regulating the exhaust pressure, the amount of air injected into the fuel tanks can be matched exactly with the engines' load and the vessel's speed, thereby reducing fuel consumption.
  • Optimisation of the adjustable propeller blades contributes to reduced energy consumption.
  • By changing the ship's propeller, its size and design can be optimised based on the vessel's average speed. This has resulted in energy savings of between 5% and 10%.
  • Frequency controlled pumps and fans - applies mainly to the seawater pumps and engine room fans.
  • Installation of regulators on the main engines to control the supply of fuel.
  • Insulation of heating pipes in the engine room allows some of the heat to be recycled on board, thereby reducing fuel consumption.
The Hull

The Hull

  • Cleaning of the hull (and propellers) reduces fouling. This results in less friction, which in turn leads to reduced fuel consumption.
  • Optimisation of the hull draft between bow and stern, which helps to reduce energy consumption.
  • By changing the ship's bulbous bow, the bulb size can be optimised based on the vessel's average speed.
Areas on board the ship

Areas on board the ship

It is not only a vessel's engines that are powered by fuel. Lamps, refrigerators, ovens, heating and ventilation - all consume fuel and in doing so also affect the environment.

  • Installation of induction cookers in the kitchen areas on board, instead of stoves that are left on all of the time because they are slow to start up.
  • Installation of LED lights on board - e.g., on car decks. In some cases they are linked to motion detectors so that they do not need to be on when no one is in those areas.
  • Cabin windows with solar film that blocks out 82% of the sun's radiant heat. The result is less fuel consumption in the ship's cooling system.
Measures carried out on shore

Measures carried out on shore

  • An energy management system (EMS) is a commercial tool used by shore-based employees to monitor the ships' energy consumption and to enable best practice to be applied between various ships.
  • By adjusting the schedule, the ship's average speed can be adjusted, which also affects fuel consumption.
  • In several of the ports where Stena Line operates, it is possible to connect the vessels to shore-based power when they are berthed. This allows the auxiliary engines on board to be turned off, which saves oil and helps to reduces emissions. A project is also in progress in the Port of Gothenburg which involves one of the ferries (Stena Danica) being connected to the district heating network when she is berthed.
Employee training

Employee training

  • An e-learning course has been developed for personnel on Stena Line's ferries to educate them about how they can contribute to reducing energy consumption on board, both in the course of their work and by making some changes to their behaviour.
  • For vessels of the same model, competitions are sometimes arranged between them to see which vessels use the least fuel. Different shifts on the same ship sometimes compete with each other. In addition to the honour of winning, there is sometimes prize money in the pot.
  • Fuel management systems (FMS) are installed on board on all Stena Line's owned ferries. An FMS is similar to a trip computer that measures fuel and energy consumption. The system is used by the crew in the engine room and on the bridge and by some of the shore-based office staff. The system can show both real-time and historical fuel consumption.