The transportation sector faces a crucial challenge: reducing emissions while maintaining efficiency. Hydrogen, a clean-burning fuel, emerges as a promising solution, particularly for heavy-duty vehicles. However, refuelling large and powerful vehicles requires innovative solutions to ensure safety, speed, and efficiency. There are a raft of regulations and standards governing the sector, not least the J2601-5 standard protocol for high-flow fuelling of medium and heavy-duty vehicles.
It is vital to understand the complexities of the hydrogen supply chain. While the J2601-5 protocol is yet to be fully validated by real world refuelling experience, it is crucial to stay up-to-date with the latest advancements and industry best practices in order to navigate the evolving regulatory landscape and ensure that technology and refuelling infrastructure meets future demands.
As regulations evolve to accomodate larger vehicles, the sector will need to develop dispensing equipment that is specifically designed for the demands of heavy-duty hydrogen refuelling. Faster flowrates, precise measurement, and robust hardware will be required to handle increased pressures. ANGI Energy Systems’ goal is to provide solutions that facilitate rapid refuelling, minimise downtime, and ensure operator safety.
The transition to a net-zero future requires collaboration. Therefore companies must embrace technical expertise and show a commitment to innovation in order to support clean and efficient heavy-duty transportation today and in the future. Faster filling, bigger tanks: the need for speed One of the most important considerations for heavy-duty refuelling is flowrate. Unlike traditional internal combustion engine (ICE) trucks that can typically refuel within minutes, filling a large hydrogen tank on a truck or bus can take significantly longer using existing technology that was originally developed for light duty hydrogen vehicles. This can lead to bottlenecks at refuelling stations and disrupt operations. To address this, the industry is developing regulations such as the SAE J2601-5 protocol, focused on developing methods to achieve faster flowrates, with a significant increase from 60 (under existing J2601) to 300 grams per second. This could involve advancements in compressor technology, improved pipeline design, and new nozzle technologies.
Balancing speed and efficiency
Faster refuelling times are crucial for the widespread adoption of hydrogen-powered vehicles, especially for heavy-duty trucks. However, achieving this speed comes with a challenge: keeping the hydrogen cool.
The stricter J2601 standard mandated a very cold hydrogen delivery temperature (between -17.5 and -40˚C). While this cold temperature allows for quicker refuelling, it requires expensive and bulky chilling systems for stations to keep up with high flow rates for large tanks on vehicles.
Recognising this challenge, the J2601-5 standard offers a solution. It relaxes the restriction on the upper limit of hydrogen delivery temperature, allowing it to be as warm as 20˚C for H35 tanks and 0˚C for H70 tanks. While this warmer hydrogen may mean slightly slower refuelling, it significantly reduces the burden on chilling infrastructure, making it more cost-effective and manageable for stations to handle the high-demand refuelling needs of heavy-duty vehicles.
The role of vehicle communication
For efficient and safe hydrogen refuelling, reliable communication between the fuelling station and the vehicle is paramount. The vehicle provides real-time data on its fuel tank size, pressure, temperature, flowrate, and pressure limitations. This information allows the station to tailor the fuelling process to the specific needs of the vehicle, enhancing efficiency and further contributing to safety. SAE J2799, the current standard that specifies the communications hardware and software requirements for refuelling hydrogen vehicles, is currently being updated to include additional safety measures and improved dispenser-to-vehicle communications, which will be required for the higher flowrates described in J2601-5. SAE J2799 is intended to be used in conjunction with the hydrogen fuelling protocols in SAE J2601 and should enable harmonised deployment of hydrogen fuelling interfaces.
Hardware upgrades for heavy lifting
The increased flowrates associated with heavy-duty refuelling necessitate robust hardware infrastructure. The industry is developing new hanging hardware specifically designed to support H70 high flowrate refuelling, which is expected to enter the market in 2026. The SAE J2600 H70 standard which governs the design of fuelling connectors, nozzles, and receptacles for hydrogen vehicles is expected to be updated before then.
Building confidence in new algorithms
The increased complexity of heavy-duty refuelling requires advanced algorithms to manage the fuelling process. However, these algorithms require thorough validation before they can be widely deployed. ANGI utilises validation methods and tools such as the HGV 4.3 standard, HYSTEP and the MC Formula Validator, which will still need to be updated to provide validation methods and tools for the new J2601-5 protocol.
J2601-5: a standard in the making
The SAE J2601-5 standard is another piece of the puzzle for heavy-duty refuelling. It outlines best practices for fuelling larger vehicles with higher capacity tanks. However, it is currently not a fully released standard and it is still classified as a technical information report (TIR). Real-world data from operational deployments are required to validate its effectiveness before it can be formally adopted by industry.
Unification: a global standard for the hydrogen sector
The hydrogen sector is taking a giant leap towards standardisation. A critical aspect of this is aligning the ongoing development of the ISO 19880 series standards with the emerging SAE J2601 standard refuelling protocols. This unification will create a global language for hydrogen refuelling, ensuring seamless compatibility across borders. ISO working groups 24 and 38 are making updates to the ISO fuelling protocols for hydrogen-fuelled vehicles and are working closely with SAE to align as much as possible.
This has major implications for the heavy-duty vehicle sector. With unified standards, components and processes developed anywhere can be readily adopted for hydrogen refuelling infrastructure worldwide. This fosters innovation and streamlines the rollout of this vital technology, accelerating the transition to clean heavy-duty transportation.
Conclusion
The focus on heavy-duty refuelling within the hydrogen transport sector signifies a commitment to decarbonising even the most challenging transportation segments. By addressing issues like flowrate, measurement accuracy, temperature and pressure control, vehicle communication, and hardware upgrades, the industry paves the way for a more efficient and sustainable future. Continuous development in validation methods and the adoption of emerging standards like J2601-5 will further strengthen confidence in this technology. As these advancements materialise and more hydrogen combustion and fuel cell vehicles come to market, heavy-duty hydrogen refuelling will become more mainstream, enabling the cleaner and more sustainable transportation of goods and people across the globe.