Abstract
This paper evaluates the efficacy and efficiency of fleet decarbonization pathways. We compare three different regulatory approaches, including the recent International Maritime Organization (IMO) Net-Zero Framework. To compare each pathway, we define a Strategic Tramp Fleet Renewal and Retrofit Problem with emission reduction integrated with tactical and operations decisions. The strategic decisions are the power system and fuel selection for the fleet over the planning horizon. The tactical and operations decisions include the fleet deployment and the transportation demand satisfaction. We analyze a case study using data from a tramp shipping operator, where diesel, LNG, ammonia, LPG, and methanol are the available fuels. The experimental results confirms that Bio-methanol and E-ammonia are most relevant alternative fuels to achieve consistent emissions reductions. We conclude by studying the marginal contribution of the most relevant fuels, discussing the different trajectories’ cost efficiencies, and observing that the IMO Net-Zero Framework is very expensive for shipping operators.