One of the most promising power sources for reaching the aviation sector’s long-term decarbonization ambitions is hydrogen. Although on-board hydrogen systems, including fuel cells, have received substantial maintenance, repair, investigation, and overhaul (MRO) aspect has largely gone untouched. Based on a literature analysis and comparison with the automobile sector, this research examines fuel cells from an MRO aspect. It also investigates how well MRO companies’ business models and critical resources are now equipped to supply future MRO services. It is demonstrated that fuel cells necessitate considerable MRO activities in order to fulfil the aviation sector’s standards for pricing, safety, and, most importantly, durability. To some extent, experience from the automobile industry may be used, notably in terms of facilities needs and staff certification.
Fuel Cell MRO at the Cutting Edge:
While fuel cells are a relatively new technology for aviation, substantial experience with fuel cell application has been acquired in other areas. This includes determining the best type of fuel cell for a specific application, as detailed in the paper’s further analyses. The significance of MRO can be determined according to the type of fuel cell employed. A comparison with the automobile industry can provide more insights into fuel cell MRO.
Types of Fuel Cells
There are several varieties of fuel cells, each with its own set of benefits and drawbacks. As a result, which fuel cell types are most relevant for aviation uses and how they relate to fuel cells used in automobile applications must be identified.
The polymer electrolyte membrane fuel cell has been shown to be the most promising form of fuel cell for aviation uses and is thus employed in the majority of the projects mentioned. This is attributed to its high efficiency (40-60%), high power density (1.6 kW/kg), wide power application range (10 W to 1 MW), quick start-up and shut-down periods due to low operating temperature (60-90 C), cold start and cold storage capabilities, and low noise emissions. The solid oxide fuel cell, which has a potentially greater efficiency (60-65%), is another intriguing form of cell that might be employed in aircraft.
The Function of Fuel Cell MRO:
The difficulty posed by the limited durability and dependability of fuel cells creates particularly high expectations and emphasises the need for PEMFC MRO. MRO can play a critical role in overcoming this difficulty, but it is only addressed in part in the existing research. The current focus of PEMFC MRO research is on predictive health management, which has switched in recent years Hashimasa and Numata from concern with deterioration and performance consequences. There is an emphasis on manufacturing processes in larger PEMFC research, with the goal of lowering the acquisition cost of PEMFCs and overcoming technical difficulties, particularly the maximum energy output in the MW scale. Traditional maintenance operations such as frequent inspection, repair of damaged parts, and planned component replacement have largely been disregarded and neglected, despite the fact that fuel-cell maintenance can result in considerable lifespan extension. This is mostly due to the fact that PEMFCs are not yet commonly used. They have not proceeded past the demonstration phase in the aviation sector, in particular.
It is also impossible to compare PEMFC’s MRO to that of other sectors. While MRO generally adheres to the same concepts and purposes, such as guaranteeing operational readiness, cost savings, regulatory compliance, and resale value, aviation MRO has the primary goal of assuring airworthiness and, hence, the safety of flight operations.
MRO of Fuel Cells in Automotive and Aviation:
PEMFCs are the industry standard for hydrogen-powered cars and buses in the automotive industry, and while the market share of fuel-cell-powered vehicles is currently tiny, this has allowed expertise in the operation and maintenance of PEMFCs to be gained, some of which is transferable to the aviation sector. Furthermore, a notion related to airworthiness exists in the car industry, known as roadworthiness. Although the regulations are not as severe and internationalised, it has resulted in comparable certification and regulating methods. Publicly funded hydrogen-powered bus initiatives, in particular, give a foundation on which to develop. Another area of commonality is how hydrogen components are handled in maintenance facilities. To operate safely with hydrogen, automobile workshops must be appropriately equipped, such as by requiring the use of hydrogen concentration monitors installed below the ceiling. A critical concentration is often defined as 20% of the lower explosive limit of 4% hydrogen in air by volume; hence, 0.8% causes a pre-alarm, which becomes a main alert if the concentration doubles and reaches 1.6%. When sensors detect a critical hydrogen concentration, a robust ventilation system and/or extra vents should be opened if the roof design allows it.
Fuel-Cell MRO Technological Analysis in Aviation:
The study is separated into two parts to better examine the PEMFC. The chemical energy freed during the electrochemical reaction of hydrogen and oxygen is converted into electrical energy, thermal energy, and water using PEMFCs. In practice, this necessitates a complicated surrounding system. This covers things like hydrogen supply and cooling, as well as water management and electrical systems. The surrounding system is first studied. Second, the stack, or core of the fuel cell, is evaluated.
System of Surroundings:
The system around the stack might vary in shape and appearance, and various system components are necessary based on the environment and application. In underwater applications, for example, hydrogen is kept in metal hydride cylinders, while oxygen is stored in liquid form, a completely different technique from the previously stated solution for aeroplanes. Schröder, Campanari, Correa, and Lapena-Rey, for example, present specific designs for commercial aviation PEMFC systems, whereas An Marinaro, Suewatanakul, Kim and Kwon, and Bradley discuss layouts for smaller unmanned aerial vehicles.
Regional Analyses:
Because the United States has a large border, surveillance measures are required to guarantee national security. This has resulted in an upsurge in demand for fuel-cell-powered UAVs with improved endurance capabilities to meet the operational requirements of US border patrol personnel. Furthermore, the large deployment of tactical UAVs in military and defence applications helps the region’s domestic UAV fuel-cell industry. A large chunk of the market for fuel cell UAVs is driven by their inherent longer endurance, which makes them ideal for a variety of tasks such as surveillance and real-time data transfer. The rising demand for UAVs has given rise to a number of new business possibilities in the region. Numerous contracts are being awarded to cater to diverse customers. For example, Ballard Power Systems’ subsidiary Protonex obtained purchase orders for the supply of 13 new fuel-cell propulsion systems for installation onboard the US Navy’s Ion Tiger UAVs, with delivery anticipated for the end of the year. Product innovation is a main market emphasis, and suppliers are always investing in R&D operations to improve their product offerings.
Recent Development:
In 2022: Through its revolutionary hydrogen fuel cell technology, HyRail, Proton Motor allowed railway and engineering manufacturers, integrators, and SMEs to realise green emission-free fuel cell electric motors.
In 2022: Doosan Fuel Cell Co., Ltd., along with Samsung C&T and the Korea Institute of Energy Research, inked a Memorandum of Understanding (MoU) with Korea Southern Power. The MOU calls for collaboration in the development of fuel cell-coupled CU technologies as well as ammonia fuel cell demonstration projects.
In 2021: FuelCell Energy has completed site construction and begun conditional commercial operation of its 7.4-megawatt SureSource fuel cell facility in Yaphank, Long Island, New York.