The current yacht industry must reduce its environmental impact significantly in order to comply with increasingly stringent regulations and goals. Building only sustainable yachts is not sufficient to reduce the impacts of yachting, existing ships must be adjusted as well. With a sustainable refit, existing vessels can be altered to reduce operational emissions in order to reduce their impact. Several options are available to increase the efficiency of a ship or reduce its emissions.
In order to evaluate which refit options are most suitable for specific yachts an overview is needed of the impact reduction and cost effectiveness of these measures. The aim of this research is therefore to create an appraisal tool to determine the cost-effectiveness of yacht operational emissions reducing refit options. In order to gain insight into the current refit process an overview of the service area’s was made and data on past refits was analysed. In order to define the fitting decision making method, an analysis was made of abatement decision making in literature. Furthermore, the refit process was analysed and distributed into three phases: the upstream, yard processes, and downstream. Since themajority of emissions are in the operational part, the focus of this research is on this phase. The operational emissions consist of exhaust-, noise- and sewage emissions. In the selection tool theWell to Tank (WTT) and Tank toWell (TTW) emissions are taken into account. The impacts to ecosystems, human health and climate by different air emissions were evaluated, as well as methods to express them. The main environmental impacts by yacht operational emissions are eutrophication, acidification, global warming, photochemical oxidation, particulate matter and ozone layer depletion.
With the Marginal Abatement Cost Curve, an overview can be created of the impact abatement and marginal costs of refit options. In this research the curve was constructed both for both CO2-equivalent units, to assess the difference in global warming potential, and for external cost reductions, in order to take into account the total impact, including other harmful effects of emissions, set out over the listed abatements. To provide a complete overview of the financial aspect a business case was added to supplement the curves with, among others, payback time.
The tool was then supplemented with a selection of five refit options, ranging from power generating and power consuming to emission reducing. Solar panels were implemented as power generating solution. As propulsionary power consuming refit option, anti-fouling techniques were analysed. A waste heat recovery system as well as LED light implementation were analysed as auxiliary power consumption reducing options. As an emission reducing option the implementation of a selective catalytic redactor system was analysed. These refit operations were evaluated in terms of technology, refit implementation and finally capital- and operational expenditure costs. The specific inputs needed for implementing these refit options in the model were evaluated and added to the tool.
The model was subjected to multiple case studies in order to asses the impact of length, fuel price and biofuel implementation on the cost effectiveness of refit options. The first case is done on a 54 meter ship, which is the average refit length, using the current fuel price. The implementation of these refit options could reduce its Global Warming Potential (GWP) with 23 % and its total impact with 54 % at a yearly cost increase of 79.7 k", or 35% extra on fuel expenditures. A fuel price increase of 158 % resulted in the refit options being cost neutral. Using biofuel, Hydrotreated Vegetable Oil (HVO), the GWP is reduced by 78%and external costs are reduced by 70%at a yearly cost increase of 167.4 k", or 47%. The same situations were evaluated for a 100 meter ship, in which similar relative impact reductions were found at a smaller increase of yearly costs.
The results of these studies showed that using HVO for GWP reduction and a SCR unit for reducing NOx impact can significantly decrease the impact of a yacht. Higher fuel prices of HVO make efficiency improving refit options more cost effective, since fuel saving revenue is higher. HVO therefore provides a possibility for yachts to decrease their impact significantly without large investment at a relatively small extra operational expenditure cost. The combination of MACC’s and a business case present an opportunity to present an overview of cost effectiveness of all refit options, if supplemented.
