E-Navigation Tools and GHG-Emissions

The IMO and IALA are also looking at the possibility of using e-navigation to reduce carbon, sulphur and nitrogen emissions from ships. This would be done through more efficient vessel route handling at sea and also while on pilotage and berthing. It has also been proposed to use e-navigation data to audit the measurement of emissions data if and when they need to be reported. The main and fundamental change with the introduction of e-navigation will be the closer relation between the “officer of the watch” on the bridge and the assistance provided from shore-based stations in carrying out the safe navigation of the ship. It is still difficult to predict what the technological developments will be in the future to allow the development of e-navigation so the potential impacts on efforts to reduce GHG emissions are still difficult to estimate. However, the ship navigational information (GPS data) has successfully been used to estimate shipping fuel consumption and GHG emissions. There is currently equipment or systems either in use or at an advance state of development that will form part of a shipboard e-navigation system that may be used to reduce GHG emissions. Examples are:

  • Voyage performance analysis: This system can measure ship speed, shaft propulsion power and external environmental situation such as wind and waves that could be used for monitoring voyage performance and to identify performance deviations. These performance deviations that may be positive as well as negative could be used to improve the ships environmental performance (MariEMS 2017).
  • ECDIS (Electronic Chart Display and Information System): The electronic chart and information system has the potential for improving navigational practices and reduce GHG emissions.
  • Autopilot precision and effectiveness: A new generation of autopilots is under development that can automatically adapt the steering actions to prevailing weather conditions and sea state. These systems include dedicated functions such as 'precision' and 'economy' modes depending on the requirement of the ship. If the autopilot is operating in economy mode it would reduce rudder movements, thus reducing the drag of the rudder that will save fuel (MariEMS 2017).
  • Manoeuvring assistance tools: With the introduction of modern information and communication technologies, more and more assistance tools have been introduced additionally to standard mandatory navigational bridge equipment. Among those integrated systems there are tools for planning and monitoring purposes on the macro and micro level. Macro planning deals with waypoint planning for the sea trail of any voyage from point A to B. Micro planning is dedicated to the planning of detailed steering sequences for complex manoeuvres in harbour areas, even including berthing operations. Once the planning process is completed and approved, the bridge team can follow the steering sequence using any dedicated display to check the plan is being kept. The use of sophisticated planning and monitoring tools optimizes the number of elementary manoeuvres in order to meet the requirements for the safety of navigation while also meeting the requirements for the minimum use of the steering equipment and saving fuel and time and simultaneously reduce GHG emissions when operating in coastal and harbour areas (MariEMS 2017).
  • Integrated navigational systems: This can achieve fuel savings by keeping cross track error to a minimum while in passage. This technology has been brought about by extremely accurate GPS position information, which can calculate the ships position down to a few meters with the capability of giving accurate heading information. With this system, better course control is achieved by requiring less frequent and smaller corrections to minimize rudder resistance. Generally, a ship is most efficient with regard to rudder position, when the rudder is mid-ships and not carrying any helm in either direction due to wind or sea conditions (MariEMS 2017).
  • Computerized manoeuvring assistance tools: This takes into account the prevailing environmental conditions such as wind and current, ship condition, current course, speed, draught and the trim of the vessel. The systems can adapt the manoeuvring characteristics to the external environmental condition to ensure efficient use of energy and resources and minimize emissions of GHG. Elementary manoeuvres are defined as each single manoeuvre or command of rudder, engine and thrusters or other steering equipment. Once the planning process is completed and approved, the bridge team can follow the steering sequence using any dedicated display to check the plan is being followed. The use of these sophisticated planning and monitoring tools optimises the number of manoeuvres for safe navigation while maintaining minimum use of the steering equipment to saving fuel and time reducing GHG emissions when operating in coastal and harbour areas (MariEMS 2017).