As the marine industry is embracing decarbonisation as a fact of life it is now possible to look at the challenge in a new and positive way, profitable decarbonisation. For many years solutions have been available to reduce emissions but it is only recently that the business case to drive this paradygm shift has become clear – one that delivers reduced emissions for retrofits and new build projects and adds real competitive advantage. A strategic approach to this challenge is necessary and will include three components depending on a vessel’s operating profile :
Electrical solutions and their role on vessels has clearly been part of a vessel design for many years, such as Diesel-Electric-propulsion or shaft generators, etc. However, the share of green energy from renewable sources such as wind, water, solar in the land based electrical grid has in recent years increased significantly and will continue to do so. Therefore, by combining this shift in shore based green energy with vessels capable of utilising shore connection will enable vessels to reduce emissions dramatically.
Flexibility was once not a consideration in vessel design and as seen when slow steaming was the favoured solution to reducing emissions for many vessels, this lack of flexibility meant some vessel will never be fully optimised. The use of electrical systems onboard will enable smarter propulsion systems that are more resilient and flexible enough to adapt to future changing needs more easily.
Below are some examples of actual systems for a variety of vessel types.
The hybrid solution of shaft generators, converters, and transformers, includes a 5000 kWh energy storage system, enables zero emissions operation while in port to meet RINA Green Plus class notation and deliver fuel savings.
Shuttle tankers benefit from this flexible solution due to their dynamic positioning (DP) requirement. The power required by DP varies, but the diesel electric solution allows the engine loads to be adjusted depending on environmental factors. By using a diesel electric solution, the engines are used for steaming and DP, which means the total installed power can be reduced. The flexible hybrid solution allows the vessel to operate the engines at their optimal load in DP and steaming by providing peak shaving which removes variable loads and also acts as spinning reserve. This reduces fuel consumption, associated emissions and increases engine maintenance intervals.
With the variable load need for tug operations is ideally suited to a hybrid configuration – offering peak shaving and load balancing so the engines can operate at their optimal level. The hybrid system also allows the tug to run fully electrical in low load conditions in and out of harbour and when waiting and power boost when additional power is needed. Hybrid can also allow smokeless start.
For a fishing vessel with variable loads the hybrid system allows the main engine to run at optimal load and the total installed power can be reduced, this allows the main engine installation to be smaller to match the power needed. The battery and aux engines supply additional power for propulsion boost in harsh weather conditions and offer peak shaving.
The shaft generator system uses a variable frequency converter to provide stable auxiliary power. When the main engine is running on gas, the Shaft Generator allows you to generate the whole electrical power needed onboard with a very good SFOC and close to zero maintenance costs for the SG System.