Examining the Feasibility of Liquefied Hydrogen Gas as an Alternative Marine Fuel
Introduction
The maritime industry faces the challenge of reducing its greenhouse gas (GHG) emissions to meet the targets set by the International Maritime Organization (IMO) and the Paris Agreement. According to the IMO, the shipping sector accounted for about 2.9% of global CO2 emissions in 2018, and these emissions could increase by 50-250% by 2050 under a business-as-usual scenario (IMO, 2020). To achieve the IMO’s goal of reducing GHG emissions by at least 50% by 2050 compared to 2008 levels, the industry needs to adopt low-carbon or zero-carbon fuels and technologies.
One of the potential alternative fuels for maritime decarbonization is liquefied hydrogen gas (LHG), which is hydrogen that has been cooled to -253°C and compressed to a liquid state. LHG has several advantages over conventional marine fuels, such as high energy density, zero carbon emissions, and compatibility with fuel cells and combustion engines. However, LHG also poses some technical and safety challenges, such as high storage and distribution costs, low availability and maturity, and flammability and cryogenic hazards. Therefore, this paper aims to examine the feasibility of LHG as an alternative marine fuel by analyzing its benefits and drawbacks from environmental, economic, and social perspectives.
Environmental Benefits
The main environmental benefit of LHG is that it does not produce any carbon emissions or other pollutants when combusted or used in fuel cells. This means that LHG can help the maritime industry achieve its GHG reduction targets and improve air quality in ports and coastal areas. Moreover, LHG can be produced from renewable sources, such as solar, wind, or hydro power, through water electrolysis. This would reduce the dependence on fossil fuels and enhance the sustainability of the energy system.
According to a study by DNV (2021), LHG could reduce CO2 emissions by 99%, NOx emissions by 85%, SOx emissions by 100%, and particulate matter emissions by 100% compared to heavy fuel oil (HFO), which is the most widely used marine fuel today. The study also estimated that LHG could reduce the total cost of ownership (TCO) of a ship by 9-18% compared to HFO, depending on the ship type and size. The TCO includes capital expenditures (CAPEX), operational expenditures (OPEX), and fuel costs.
Economic Challenges
The main economic challenge of LHG is its high production and distribution costs, which are influenced by several factors, such as electricity prices, electrolyzer efficiency, liquefaction energy requirements, storage tank size and insulation, transport distance and mode, and bunkering infrastructure. According to a study by Frontiers in Marine Science (2022), the production cost of LHG ranges from $3.5 to $6.5 per kg depending on the electricity source and location. The distribution cost of LHG ranges from $0.5 to $3 per kg depending on the transport mode and distance. The total cost of LHG delivered to ships ranges from $4 to $9.5 per kg.
In comparison, the current price of HFO is about $0.4 per kg (Ship & Bunker, 2022). This means that LHG is about 10-24 times more expensive than HFO at present. Therefore, to make LHG competitive with conventional marine fuels, there is a need for policy interventions, such as carbon pricing, subsidies, incentives, or regulations that can internalize the external costs of GHG emissions and pollution.
Social Implications
The main social implication of LHG is its impact on the safety and skills of the maritime workforce. LHG has different properties and characteristics than conventional marine fuels, which require special handling and operation procedures. For example, LHG is highly flammable and explosive when mixed with air in certain concentrations. It also has a very low boiling point (-253°C), which can cause severe frostbite or cold burns if it comes into contact with human skin or eyes. Therefore, there is a need for adequate training and education for seafarers and port workers who will handle or use LHG.
According to a handbook by DNV (2021), there are several safety measures that can be implemented to mitigate the risks associated with LHG. These include using double-walled tanks with vacuum insulation, installing leak detection and ventilation systems, applying safety distances and barriers, following strict operational protocols and emergency procedures, and wearing appropriate personal protective equipment. The handbook also provides guidance on how to design, build, and operate LHG-fuelled vessels, covering aspects such as fuel storage, delivery, bunkering, consumption, and disposal.
Conclusion
LHG is a promising alternative fuel for the maritime industry that can offer significant environmental benefits and potential economic savings. However, LHG also faces some technical and safety challenges that need to be overcome to increase its availability and maturity. Therefore, there is a need for further research and development, policy support, and stakeholder collaboration to facilitate the adoption of LHG as an alternative marine fuel.
References
DNV (2021). Handbook for hydrogen-fuelled vessels. Retrieved from https://www.iims.org.uk/wp-content/uploads/2021/07/Handbook_for_hydrogen-fuelled_vessels.pdf
Frontiers in Marine Science (2022). The use of alternative fuels for maritime decarbonization: A review of the current status and future prospects. Retrieved from https://www.frontiersin.org/articles/10.3389/fmars.2022.1082453/full
IMO (2020). Fourth IMO GHG study 2020. Retrieved from https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/GHG%20Study%20Executive%20Summary%20-%20English.pdf
Ship & Bunker (2022). Bunker prices. Retrieved from https://shipandbunker.com/prices
