Comparing fuels and emission reduction technologies for sustainable shipping: A sustainability index weighting life cycle emissions and costs

Abstract

Maritime transport produces close to 3% of global greenhouse gas emissions. Furthermore, other maritime transport emission compounds degrade air quality, which can significantly affect human health, especially near populated areas. A variety of non-fossil fuel products and technical solutions designed to reduce emissions are currently available on the market. However, the associated investments and operating costs are highly dependent on a number of factors, including the specific operating profile and sailing environment, as well as the regional regulatory framework and economic trends. For ship owners seeking an environmentally sustainable solution that is also economically viable, a multidisciplinary decision-making process is required. To facilitate decision-making, we present an Excel-based analysis model (the Multi-Criteria Sustainability Index Model, or MCSIM) for comparing the environmental effects of various fuels (heavy fuel oil, marine gas oil, liquefied natural gas), nitrogen oxide abatement systems (selective catalytic reduction, exhaust gas recirculation, water in fuel systems), and sulfur scrubbers (open and closed loop). The comparison is based on life cycle emission analysis (well-to-wake), combined with investment and maintenance cost estimates. As the assessment endpoint, we apply a sustainability index consisting of environmental and economic sub-indexes. The environmental index encompasses a range of factors, including global warming, acidification, eutrophication, and human health. This paper introduces the key features of the model and illustrates its application in eight scenarios. While the scenarios presented are situated in the Baltic Sea environment, the model is applicable in a variety of geographical areas. Built on Excel, the model allows users to create their own scenarios, make modifications, and gain familiarity with the calculation routines, thereby ensuring transparency in the calculation process.