This master’s thesis explores an alternative approach to enhance the emission performance and energy efficiency of offshore installation vessels without expensive retrofits. The concept involves employing swappable energy containers, currently used for inland cargo and tug vessels, for offshore installation vessels. These containers are filled with sustainable alternative energy sources and operate alongside conventional internal combustion engines. The study considers various technical architectures to achieve this objective.

The need for a global energy transition to mitigate the climate crisis has led to international initiatives, such as the International Maritime Organization’s (IMO) target to reduce carbon dioxide emissions from shipping by 40% by 2030, 70% by 2040, and near-zero by 2050. The greenhouse gas emission share of the shipping industry is currently marginal in the context of global greenhouse pollution. However, this should not serve as an excuse to burn fossil fuels, as the share would inevitably increase if business as usual continues. Nonetheless, the quantity of emissions remains substantial, and significant gains can be realized by enhancing the efficiency of individual sectors. Undoubtedly, every effort should be made to replace fossil fuels with renewable and sustainable alternative energy sources in the long run, meeting IMO’s 2050 goals. Until that time, enhancing the overall efficiency and emission performance of the current vessels seems like the way forward to meet intermediate targets.

This thesis assessed whether energy containers can significantly improve the total emission performance for offshore installation vessels, if not, make such a vessel comply with the IMO's climate targets for 2030. However, the required number of batteries has a significant impact on the levelized fuel cost, therefore the most effective solution can be found with the largest relative emission reductions. Nevertheless, the complete elimination of greenhouse gas emissions can only be achieved by transitioning from fossil fuels to renewable and sustainable alternative energy sources. Enhancement of the fuel efficiency through a marginal number of battery containers with strategies such as enhanced dynamic behaviour, boost capacity or spinning reserve, could then contribute to the cost-effectiveness of these renewable fuels.

Offshore lifting operations must have reduced payload motion to increase safety and reduce operating time. When payload is retrieved from the splash zone to the deck, besides the crane block, no additional control can be applied on the underactuated system. Existing studies either assume more control over the payload or develop a control system based on a new crane. To reduce payload motion on current crane vessels, a conceptual model needs to be developed.

In this thesis, various state-of-the-art solutions are considered based on four criteria: Time reduction, motion reduction, initial investment required and power required. Eventually, the quantified criteria and an analytic hierarchy process established that the most promising concept is based on an automated side loader of a garbage truck.

The selected concept is developed based on a design process that focuses on optimized material usage. The geometry is determined according to requirements and forms the starting point of the circular design process. A dynamic analysis is conducted to obtain the dynamic response of the payload and eventually the reduced payload motion. The design cycle is complete after a finite element analysis has been conducted to verify the structural integrity of the model. After more than 20 cycles of the design process, the conceptual model is optimized and over 85% of motion is reduced in the X direction. The payload motion in Y- and Z-direction is 20% and 29% respectively.

The simulation results in this study show that the conceptual model is able to reduce the payload motion during offshore lifting operations whilst staying within the limits set by offshore standards. The motion reduction of the payload creates a safer and more efficient environment to execute offshore lifting operations.