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.