The maritime industry, responsible for transporting approximately 90% of global trade, has long been a cornerstone of the global economy. However, this vital sector contributes nearly 3% of global greenhouse gas emissions, underscoring the pressing need for sustainable solutions. (BBC)
If shipping were a country, it would rank among the top emitters. Worse, due to increasing trade volumes, shipping emissions could grow by up to 50% by 2050 without intervention (neste.com). Such an increase would undermine international efforts to combat climate change, highlighting the necessity for immediate and effective interventions within the shipping sector.
Green hydrogen is a clean, renewable energy source that can transform maritime shipping. As we navigate towards a zero-emission future, understanding the role of green hydrogen in decarbonising ocean freight becomes paramount. Let's embark on this journey to uncover its potential to revolutionise sea transport.
The Environmental Imperative for Decarbonising Maritime Shipping
Regulatory Pressures
The International Maritime Organization (IMO) adopted the Initial IMO Strategy for Reducing GHG Emissions from Ships in 2018, setting ambitious targets to reduce greenhouse gas emissions from international shipping.
The strategy aims to reduce the carbon intensity of international shipping by at least 40% by 2030 compared to 2008 levels and to halve total annual GHG emissions by 2050.
In July 2023, the IMO updated its strategy, committing to net-zero greenhouse gas emissions by 2050, with ambitious interim goals for 2030 and 2040. (The Guardian)
These targets underscore the IMO's commitment to aligning the maritime industry with global climate goals and promoting sustainable shipping practices.
Environmental Impact
Beyond GHG emissions, maritime shipping significantly affects air quality, particularly in coastal regions and port cities. The industry's reliance on heavy fuel oil releases sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter, which pose serious health risks to nearby populations. Moreover, these pollutants contribute to ocean acidification and biodiversity loss, further exacerbating environmental challenges.
Improving energy efficiency (through measures like slow steaming, hull design, and waste-heat recovery) has helped reduce shipping’s carbon intensity by ~30% since 2008 (wri.org). Yet efficiency gains alone cannot offset the projected growth in demand – new low- or zero-carbon fuels are required for a sustainable future.
Several fuel options are under consideration: liquefied natural gas (LNG) is already used as a transition fuel (about 25% lower CO₂ than oil-based fuels, though with methane leakage concerns, and biofuels or synthetic e-fuels can be near-neutral if sourced sustainably.
In the long term, hydrogen and ammonia are viewed as among the most promising solutions because they contain no carbon and thus offer the potential for zero greenhouse gas emissions at the point of use.
Ammonia (NH₃), which can be made from hydrogen and nitrogen, has high energy density and emits almost no CO₂ when used, but it is toxic and poses safety challenges in handling.
On the other hand, green hydrogen produces only water vapour when used as a fuel and is non-toxic, making it an attractive candidate for clean shipping.
Integrating Green Hydrogen into Maritime Vessels
The maritime industry's shift toward sustainability necessitates the adoption of alternative fuels, with green hydrogen emerging as a leading candidate. Integrating green hydrogen into maritime vessels involves evaluating propulsion technologies, retrofitting existing ships, and designing new hydrogen-powered vessels.
Hydrogen’s zero-carbon potential and flexibility (it can be used in fuel cells for electric propulsion or burned in modified engines) have put it at the forefront of maritime innovation. Nearly half of the 100+ pilot projects for zero-emission shipping identified in a 2021 Global Maritime Forum study focus on hydrogen-based fuels (csis.org)
Designing New Hydrogen-Powered Ships
Developing vessels specifically for hydrogen propulsion allows for optimised integration. New ships can be engineered with dedicated spaces for hydrogen storage and fuel cell systems, enhancing efficiency and safety.
Incorporating green hydrogen into maritime vessels involves assessing propulsion technologies, the potential for retrofitting existing ships, and designing new hydrogen-powered vessels.
While challenges persist, ongoing advancements and pilot projects indicate a promising trajectory toward sustainable maritime transportation.
Case Studies: Pioneering Hydrogen-Powered Ships
Pioneering vessels that harness hydrogen technology exemplify the maritime industry's transition to sustainable energy sources. Notable among these are the Energy Observer, the MV Sea Change, and the MF Hydra, each showcasing innovative approaches to zero-emission maritime transport.
Energy Observer: A Floating Laboratory
Launched in April 2017, the Energy Observer is a former racing catamaran transformed into the world's first vessel to produce hydrogen onboard from seawater. This self-sustaining energy system integrates renewable sources, including solar panels, wind turbines, and hydro generators.
The hydrogen production process involves desalinating seawater and then using electrolysis to separate hydrogen and oxygen, with the hydrogen stored for later use in fuel cells, providing continuous power without greenhouse gas emissions. (Energy Observer, Wikipedia)
The vessel embarked on a six-year global voyage to test and optimise its technologies, aiming to demonstrate the viability of renewable energy and hydrogen in maritime applications.
Serving as a floating laboratory, the Energy Observer has been instrumental in advancing research on energy autonomy and integrating renewable energy systems in marine environments.
Hydroville (Belgium, 2017)
In late 2017, Belgian shipowner CMB launched the Hydroville, the world’s first accredited passenger vessel powered by hydrogen(maritime-executive.com). This 14-meter ferry uses dual-fuel combustion engines that burn hydrogen (with diesel as a backup) instead of relying on fuel cells. Hydroville was a pilot project aimed at testing hydrogen technology for larger ships.
CMB chose an internal combustion approach partly because, at the time, batteries and fuel cells were deemed too costly or heavy for their needs.
The Hydroville carries up to 16 passengers on daily commutes between Antwerp and Kruibeke, demonstrating that hydrogen can be used safely in a marine environment. Its success has spurred CMB to invest further – the company formed a venture (BeHydro) to develop medium-speed hydrogen engines up to 2–3 MW for tugs, ships, and generators (splash247.com), signalling confidence that hydrogen combustion is a viable path for larger vessels.
MV Sea Change: The First Hydrogen Fuel Cell Ferry
The MV Sea Change, launched in 2021, is the world's first commercial vessel powered entirely by hydrogen fuel cells.
Developed by Zero Emission Industries (formerly Golden Gate Zero Emission Marine), this 70-foot catamaran ferry operates in the San Francisco Bay Area. The vessel's power system comprises 360 kW of Cummins fuel cells, 246 kg of hydrogen storage tanks from Hexagon Purus, and a 100 kWh lithium-ion battery from XALT, integrated with BAE Systems' 600 kW electric propulsion system. (Zero Emission Industries, Wikipedia)
The Sea Change can travel up to 300 nautical miles at 15 knots, emitting only water vapour and requiring less maintenance than traditional diesel-powered ferries.
This project demonstrates the practical application of hydrogen fuel cell technology in commercial maritime operations, paving the way for the broader adoption of zero-emission vessels.
MF Hydra: The World's First Liquid Hydrogen-Powered Ferry
Norway's MF Hydra, launched in 2021, is the world's first ferry powered by liquid hydrogen. Developed by Norled, a Norwegian transport company, it operates on Norway's Hjelmeland–Nesvik route. (maritime-executive.com)
The ferry has two 200 kW fuel cells from Ballard Power Systems and can accommodate up to 300 passengers and 80 cars. Liquid hydrogen has a higher energy density than compressed hydrogen gas, enabling longer operational ranges without frequent refuelling.
The MF Hydra exemplifies hydrogen's potential for decarbonising short-sea shipping routes and serves as a model for future hydrogen-powered ferries.
Infrastructure and Economic Considerations
The transition to green hydrogen as a maritime fuel necessitates substantial infrastructure developments and a thorough economic feasibility analysis. Establishing hydrogen bunkering facilities, assessing the financial viability of hydrogen production and distribution, and implementing supportive policy incentives are pivotal to integrating green hydrogen into the shipping industry.
Hydrogen Bunkering Facilities
Developing hydrogen bunkering infrastructure is essential for the widespread adoption of hydrogen-powered vessels. Key considerations include:
- Port Adaptations: Major ports must have facilities to store and dispense hydrogen safely. This involves constructing specialised storage tanks and refuelling stations capable of handling hydrogen's unique properties, such as its low boiling point and high diffusivity.
- Safety Protocols: Comprehensive personnel training and adherence to international safety standards are imperative to mitigate risks associated with hydrogen bunkering operations.
- Production Costs: Green hydrogen production is currently more expensive than conventional fuels, primarily due to the high costs associated with electrolysis and renewable energy sources. However, technological advancements are driving efficiencies.
Challenges and Future Outlook
Integrating green hydrogen into maritime shipping presents significant challenges and promising prospects. Addressing technical, economic, and infrastructural obstacles is crucial to harnessing its full potential in decarbonising ocean freight.
Technical Challenges
- Storage and Transportation: Hydrogen's low energy density necessitates storage under high pressure or extremely low temperatures (-253°C for liquid hydrogen), posing technical and safety challenges. Developing materials and systems capable of safely and efficiently storing and transporting hydrogen is imperative.
- Energy Density: Compared to traditional marine fuels, hydrogen has a lower volumetric energy density, requiring larger storage volumes. This limitation affects vessel design and cargo capacity, necessitating innovative engineering solutions to optimise space and efficiency.
- Safety Concerns: Comprehensive safety measures, including advanced detection systems and crew training, must be implemented to mitigate risks associated with hydrogen use in maritime environments.
- Economic Viability: The high costs of green hydrogen production, storage, and distribution hinder widespread adoption. Achieving cost parity with conventional fuels requires technological advancements and economies of scale.
- Infrastructure Development: A comprehensive hydrogen refuelling infrastructure poses a significant barrier. Establishing hydrogen bunkering facilities at major ports is essential to support the operational needs of hydrogen-powered vessels.
- Regulatory Frameworks: The absence of standardised regulations for hydrogen use in shipping creates uncertainty. Developing clear and consistent policies is vital to encouraging investment and ensuring safe implementation.
Future Prospects
- Technological Innovations: Ongoing research aims to enhance hydrogen production and storage technologies. A benefit of hydrogen engines is that they can handle the enormous power outputs needed for huge ships – something fuel cell systems are still scaling up, too. For example, a hydrogen internal combustion engine in the dozens of megawatts could one day power an ocean-going tanker or container ship.
- Pilot Projects and Collaborations: Initiatives like the Energy Observer and MV Sea Change demonstrate the feasibility of hydrogen-powered vessels. These projects serve as testbeds for refining technologies and operational practices, paving the way for broader adoption.
- Policy Incentives: Governmental support through subsidies, tax incentives, and research and infrastructure development funding can accelerate the transition. Policies promoting renewable energy integration and carbon pricing will further enhance green hydrogen's competitiveness.
- Environmental Imperatives: The global push to reduce greenhouse gas emissions positions green hydrogen as a key component in achieving maritime decarbonisation goals. Its adoption aligns with international commitments to combat climate change and promotes sustainable shipping practices.
While challenges persist, the future of green hydrogen in maritime shipping is promising. Collaborative efforts among industry stakeholders, policymakers, and researchers are essential to overcome obstacles and realise a sustainable, zero-emission future for ocean freight.
Conclusion
As the maritime industry charts a course towards sustainability, green hydrogen emerges as a beacon of hope. Its potential to drastically reduce emissions and propel ocean freight into an eco-friendly era is undeniable.
However, realising this potential requires collaborative efforts from industry stakeholders, policymakers, and technological innovators. Embracing green hydrogen signifies a commitment to environmental stewardship.
It heralds a new chapter in maritime history—one in which the waves we traverse are as clean as the energy that drives us forward.
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