Decarbonization of Estonian ferry lines – challenges and opportunities

Decarbonization in the shipping industry plays a central role in global research and innovation activities. Ways to achieve zero-emission shipping include energy efficiency improvements, operational changes, the use of non-fossil fuels, retrofit and redesign of ships. Although the environmental regulations of the European Commission and the International Maritime Organization (IMO) apply only to ships above 5000 GT, the local industry representatives and authorities in many European counties also target greenhouse gas (GHG) emissions reduction from a wider shipping sector, including smaller ships and island ferries. To achieve the GHG emissions reductions, low-carbon fuels such as biodiesel, hydrogen, and its derivatives have been proposed for ferries along with direct electrification. From the design and operation viewpoint, these alternatives involve higher investment risk, including (a) capital-intensive infrastructure requirements, (b) powertrain implementation and onboard storage sizing, and (c) fuel availability and price volatility. This study focuses on an Estonian ferry line, which serves as the primary means of transportation for connecting the mainland. Consequently, it plays a critical role in facilitating the mobility of cargo and passengers to and from the islands. We analyse possible future energy system development paths to evaluate potential alternative fuels, based on existing ferries and local port infrastructure. Subsequently, we develop and apply an energy-transport optimization model to analyse alternative fuel investments from a techno-economic-environmental viewpoint. Finally, we present a preliminary comparative analysis of GHG emissions reductions and operating costs from the perspective of energy consumption, supporting the industry’s decision makers in evaluating the future competitiveness of the shipping lines.