Posted: February 26th, 2023
Analysis of Low-Carbon Alternative Marine Fuels to Support Decarbonization of Short-Sea Shipping
Analysis of Low-Carbon Alternative Marine Fuels to Support Decarbonization of Short-Sea Shipping
Short-sea shipping (SSS) is a vital component of the global maritime transport system, accounting for about 40% of the total cargo volume and 25% of the total CO2 emissions from shipping (European Commission, 2021). SSS refers to the movement of goods and passengers by sea over relatively short distances, typically within or between neighbouring countries. SSS can provide a more efficient, cost-effective and environmentally friendly alternative to road transport, especially for congested regions and islands.
However, SSS also faces significant challenges in meeting the ambitious decarbonization targets set by the International Maritime Organization (IMO) and the European Union (EU). The IMO aims to reduce the carbon intensity of international shipping by at least 40% by 2030 and by 70% by 2050, compared to 2008 levels, and to achieve net-zero emissions by the end of this century. The EU has a more stringent goal of reducing greenhouse gas (GHG) emissions from maritime transport by at least 55% by 2030 and by 90% by 2050, compared to 1990 levels, and to include shipping in its Emissions Trading System (ETS) from 2023 onwards.
One of the main strategies to achieve these goals is to switch from conventional fossil fuels, such as heavy fuel oil (HFO) and marine diesel oil (MDO), to low-carbon alternative fuels, such as liquefied natural gas (LNG), biofuels, hydrogen, ammonia and methanol. These fuels can offer significant reductions in GHG emissions, as well as other air pollutants, such as sulphur oxides (SOx), nitrogen oxides (NOx) and particulate matter (PM). However, they also pose various technical, economic and regulatory challenges for their adoption and deployment in SSS.
This blog post aims to provide an overview of the main characteristics, advantages and disadvantages of these alternative fuels for SSS, based on a recent study by Wang et al. (2022). The study assessed the techno-economic feasibility and environmental performance of six alternative fuels (LNG, biodiesel, bioethanol, hydrogen, ammonia and methanol) for four representative SSS routes in Europe, using a multi-criteria decision analysis (MCDA) approach. The study considered various aspects, such as fuel availability and price, fuel storage and handling, engine technology and efficiency, safety and operability, GHG emissions and abatement costs.
The main findings of the study are summarized below:
– LNG is the most mature and widely available alternative fuel for SSS, with a well-established supply chain and infrastructure. LNG can reduce GHG emissions by about 20-25% compared to HFO and MDO, as well as eliminate SOx emissions and reduce NOx and PM emissions significantly. However, LNG also has some drawbacks, such as high capital costs for fuel tanks and engines, low energy density, methane slip and venting emissions, and uncertainty about its long-term sustainability and compatibility with future regulations.
– Biofuels, such as biodiesel and bioethanol, are renewable fuels derived from biomass sources, such as vegetable oils, animal fats, waste cooking oil, sugar cane and corn. Biofuels can reduce GHG emissions by up to 80-90% compared to fossil fuels, depending on the feedstock and production process. Biofuels can also be blended with fossil fuels or used as drop-in fuels in existing engines without major modifications. However, biofuels also face some challenges, such as limited availability and scalability, high production costs and land use impacts, variability in quality and specifications, and potential compatibility issues with fuel systems and engines.
– Hydrogen is a zero-carbon fuel that can be produced from various sources, such as natural gas reforming, coal gasification or water electrolysis using renewable electricity. Hydrogen can be used in fuel cells or internal combustion engines to generate power for propulsion. Hydrogen can eliminate GHG emissions completely if produced from renewable sources or coupled with carbon capture and storage (CCS). However