Decarbonisation Technology - May 2023 Issue

Journey toward decarbonisation of the shipping industry Alternative fuels for the shipping industry are explored along with methods to increase fuel efficiencies and reduce emissions

Nathan D Wood, Robert Moorcroft and Torill Bigg Tunley Engineering

T he maritime transport industry is vital to our present-day globalised world, with approximately 90% of traded commodities reliant on shipping (OECD, 2023), (UKRI, 2023). The shipping industry is estimated to be responsible for approximately 2.5% of global CO 2 emissions or 940 MtCO 2 per year (Balcombe, et al ., 2019). An increasing number of regulations and targets are being implemented to reduce the greenhouse gas (GHG) emissions from shipping. The International Maritime Organization (IMO) has set stringent targets to reduce the carbon footprint of international shipping by at least 40% by 2030, compared to 2008 levels (EIT InnoEnergy, 2022). The 2021 EU Green Deal sets targets for a 90% reduction in port city GHG emissions by 2050 (EIT InnoEnergy, 2022). The EU has also publicly declared the need to bring shipping under its Emissions Trading System (ETS), which sets caps on the emissions of companies per annum, with financial implications for companies that breach this limit (EIT InnoEnergy, 2022). The shipping industry is actively moving towards alternative fuels to reduce its carbon footprint, with many prospective fuel types (Mallouppas & Yfantis, 2021), (Department for Transport, 2022). Both liquid natural gas (LNG) and hydrogen are gaining traction as fuels for the future (Mallouppas & Yfantis, 2021). However, questions arise from these choices surrounding sustainability and ongoing reliance on fossil fuels. Ports also play a dual role in the decarbonisation of shipping by reducing in-port GHG emissions and facilitating the reduction of

Heavy fuel oil

26%

Marine gas oil

72%

Liquid natural gas

Figure 1 Fuel use in the maritime shipping industry in 2015 (Balcombe, et al. , 2019)

at-sea GHG emissions (Psaraftis & Zis, 2022). Rotterdam is Europe’s most polluting port, with an estimated 13.7 million tonnes of CO 2 e per year, more than twice the footprint of an average coal-fired power station (T&E, 2022). With regards to sea-based emissions, as of April 2018, only 28 out of the 100 largest ports (by cargo) offered incentives for environmentally friendly ships (International Transport Forum, 2023). Current maritime fuels The shipping industry is heavily reliant on the use of fossil fuels, for example dock-side cargo handling, on-ship electricity generation, and ship propulsion. It relies on an assortment of fuels, such as heavy fuel oil (HFO), low sulphur fuel oil (LSFO), marine gas oil (MGO), marine diesel oil (MDO), and LNG (Mallouppas & Yfantis, 2021). Figure 1 shows a percentage breakdown of fuel use in the maritime shipping industry in 2015.