Hydrogen Trailer Filling Practices Continue to Evolve for Decentralized Production

by Mhamed Samet, FCHEA

As hydrogen production becomes more distributed, industry stakeholders are paying closer attention to how hydrogen moves safely and efficiently from production sites to end users. Pipelines make sense for large-volume applications, but decentralized production plants, refueling stations, and last-mile industrial delivery still rely heavily on hydrogen trailers.

A recent Mission Hydrogen webinar looked at how trailer filling practices are changing as production moves beyond traditional large industrial facilities. Presented by Dr. David Wenger of Mission Hydrogen and Wenger Engineering, the discussion outlined the growing gap between legacy trailer filling operations and newer decentralized systems tied to electrolyzers, renewable electricity sources, and third-party logistics providers.

Trailer filling itself is not new, but the operating environment around it is shifting.

From Centralized to Decentralized Operations

Traditional trailer filling systems were built around a more controlled model. Filling stations were typically located inside large chemical plants, refineries, or industrial gas facilities, often with the hydrogen producer, filling station operator, and trailer operator all under one company.

These systems generally involved:

  • Manned operation

  • Experienced onsite personnel

  • Manual trailer checks and leak testing

  • A limited number of trailer configurations

  • Type I steel tube trailers

  • Common 40-foot trailer formats

  • Operating pressures around 200 bar, and in some cases 300 bar

Type I steel trailers absorb heat effectively and carry lower hydrogen quantities than newer composite designs, so precooling and thermal management were less of a concern under this model.

Newer deployment models look different. Decentralized production facilities may connect to electrolyzers in the 2 to 10 megawatt range and sit near low-carbon electricity sources rather than inside large industrial gas complexes. These sites can serve refueling stations, industrial customers, or regional distribution networks.

Under this model, trailer fleet operators, production site owners, and filling station operators are often separate companies. Some stations operate unmanned or with only remote supervision, which puts more weight on the control system, driver procedures, and automated safety functions.

Trailer Diversity and Filling Complexity

One of the technical issues raised during the webinar was the growing diversity of trailer designs that filling stations now need to accommodate:

  • Type I steel tube trailers

  • Type II trailers

  • Type IV composite trailers

  • Trailer lengths ranging from 20-foot to 45-foot configurations

  • Pressure levels including 200, 300, 380, and 500 bar

  • Different vessel geometries, materials, and thermal characteristics

This diversity affects how filling happens. Type I steel trailers are generally simpler to fill, since the steel structure absorbs heat and the stored hydrogen mass is lower. Type IV composite trailers present more thermal management challenges, particularly at higher pressures and faster fill rates.

Factors such as initial pressure, ambient temperature, hydrogen inlet temperature, vessel type, and mass flow rate all influence final gas temperature during filling. Under European transport rules, temperature limits like the 65°C threshold set by the Agreement concerning the International Carriage of Dangerous Goods by Road can become a real operational constraint.

As a result, filling protocols increasingly need to be tailored to the specific trailer rather than applied uniformly across configurations.

Automation and Safety Controls

The move toward unmanned or partially unmanned filling stations changes safety and operational requirements. In a traditional facility, experienced operators manually review documents, run leak checks, operate valves, and monitor the fill. In decentralized systems, many of these functions shift to automation or step-by-step driver procedures.

Safety-related automation can include:

  • Driver identification

  • Trailer identification

  • Grounding verification

  • Automated valve sequencing

  • Automated hose purging

  • Leak tightness checks

  • Pressure monitoring during filling

  • Emergency stop functions

  • Remote operator notification

  • Controlled access to filling areas

Automation reduces opportunities for human error, but it does not eliminate the need for training and oversight. Drivers still need to understand the procedure, confirm the trailer is safe to fill, and follow the required connection and disconnection steps. Operators remain responsible for verifying that trailers are approved, inspected, and compatible with the filling system.

Hydrogen Quality and Trailer Records

Hydrogen quality is another consideration, particularly where hydrogen is delivered to third-party customers or used in applications with strict fuel quality requirements.

Quality can be affected by:

  • Electrolyzer operation

  • Compressor performance

  • Maintenance activities

  • Imported hydrogen supply

  • System contamination

The webinar touched on the role of integrated hydrogen quality analysis in trailer filling systems. Depending on the end use, delivered hydrogen may need to meet requirements such as ISO 14687 or SAE J2719.

Recordkeeping is also becoming more important as filling operations grow more automated and involve multiple companies. Systems may need to track:

  • Driver authorization

  • Trailer certification status

  • Inspection expiration dates

  • Hydrogen quantity delivered

  • Hydrogen quality information

  • Filling pressure and temperature data

  • Customer and invoicing information

These records support operational accountability, regulatory compliance, commercial transactions, and any future investigation of safety or quality issues.

Facility Layout and Leak Detection

The webinar also addressed broader safety considerations tied to facility design. As trailers get larger and operate at higher pressures, layout, spacing, and detection strategy matter more.

Key considerations include:

  • Spacing between trailers

  • Potential incident propagation between adjacent trailers

  • Hydrogen leak detection

  • Flame detection

  • Pressure monitoring

  • Ventilation and dispersion behavior

  • Emergency shutdown systems

  • Safe hose depressurization

  • Grounding and bonding

  • Physical barriers and access controls

Barriers and safety walls can help in some circumstances, but they need to be evaluated carefully, since they can also affect ventilation, access, or emergency egress if poorly designed.

Leak detection strategies vary by application. Pressure monitoring supports leak checks during filling, while fixed hydrogen sensors, flame detectors, or other technologies may be appropriate depending on site layout and hazard analysis.

Looking Ahead

Hydrogen trailer filling will remain an important part of hydrogen distribution, particularly for decentralized production sites, refueling stations, and last-mile delivery to industrial customers.

As the industry shifts from centralized, manned filling toward more flexible and automated systems, future work is likely to focus on:

  • Trailer-specific filling protocols

  • Automated safety validation

  • Hydrogen quality monitoring

  • Driver and operator training

  • Digital records and certification tracking

  • Compatibility with higher-pressure trailer designs

  • Precooling requirements under certain conditions

  • Improved leak detection and emergency controls

  • Facility layout and safety distance practices

Trailer filling has long been part of industrial hydrogen operations, but the application is changing. As decentralized production expands, filling systems will need to safely manage a broader range of trailer types, pressure levels, ownership models, and operating conditions.

For more information about the Mission Hydrogen webinar, click here.

ANSI Hydrogen Standards Workshop Highlights Need for Coordination Across Hydrogen Codes and Standards

by Mhamed Samet, FCHEA

As hydrogen deployment expands across production, storage, transportation, infrastructure, and end-use applications, industry stakeholders continue to focus on how codes and standards can support safe, consistent, and scalable deployment.

The American National Standards Institute (ANSI) Hydrogen Standards Workshop held June 22-23, 2026, in Washington, D.C., brought together standards development organizations, federal agencies, industry representatives, and technical experts to discuss the current hydrogen standards landscape and identify priorities for future coordination. The workshop was hosted at the American Society of Mechanical Engineers (ASME) and included discussions on standards gaps, conformity assessment, permitting, implementation challenges, and regulatory alignment.

The workshop reflected a broader industry need. Hydrogen standards are advancing across many organizations and applications, but deployment increasingly depends on how well those standards work together in real-world projects.

Hydrogen Standards and Deployment Readiness

Hydrogen technologies are moving into a wider range of commercial applications, including:

  • Production facilities

  • Bulk storage systems

  • Pipelines and distribution networks

  • Refueling infrastructure

  • Stationary fuel cell systems

  • Mobility applications

  • Industrial and chemical uses

  • Power generation and grid integration

Each of these applications depends on a different combination of codes, standards, regulations, testing requirements, and permitting processes. Many hydrogen standards already exist, but industry stakeholders continue to encounter challenges when applying them across projects that combine multiple technologies, jurisdictions, and end uses.

The workshop agenda emphasized that hydrogen deployment requires more than individual technical standards. It also requires conformity assessment tools, permitting pathways, inspection practices, training, and regulatory frameworks that can keep pace with technology development.

Conformity Assessment and Permitting

One of the central topics at the workshop was the role of conformity assessment in supporting safe deployment. Standards provide technical requirements, but those requirements must be implemented through testing, certification, inspection, and permitting programs.

Key issues include:

  • Third-party testing and certification

  • Building and fire code adoption

  • Authority having jurisdiction review

  • Federal agency requirements

  • Inspection and commissioning practices

  • Clear compliance documentation

  • Training for code officials and project developers

For hydrogen technologies, misalignment between standards and permitting pathways can create uncertainty even when strong technical standards exist. Stakeholders may face challenges when a product or system meets an applicable standard, but the permitting or inspection process does not clearly recognize that pathway.

Improving these connections can help reduce project delays, improve consistency across jurisdictions, and give authorities having jurisdiction greater confidence when reviewing hydrogen installations.

Standards Gaps and Coordination Needs

The workshop also focused on identifying standards gaps and areas where greater coordination among standards development organizations may be needed.

Hydrogen technologies often cut across traditional standards boundaries. A single project may involve pressure equipment, electrical systems, hazardous materials storage, fire protection, ventilation, controls, fueling, transportation, and environmental requirements. As a result, overlapping standards can sometimes create uncertainty for project developers, regulators, and code officials.

Areas where coordination remains important include:

  • Hydrogen production system requirements

  • High-pressure gaseous storage

  • Liquid hydrogen storage and transfer

  • Hydrogen pipelines and distribution

  • Refueling infrastructure

  • Fuel quality

  • Electrolyzer performance and safety

  • Stationary fuel cell systems

  • Hydrogen use in buildings and industrial facilities

  • Emergency response and workforce training

Workshop discussions also recognized that some areas may require additional pre-standardization research before effective standards can be developed. In these cases, incident data, demonstration project experience, laboratory testing, and field performance data can help inform future standards development.

Implementation Challenges in the Field

A recurring issue in hydrogen codes and standards discussions is not only whether standards exist, but whether they are clear, usable, and consistently applied.

Stakeholders continue to encounter implementation challenges involving:

  • Overlapping requirements

  • Different interpretations across jurisdictions

  • Limited hydrogen-specific training

  • Unclear compliance pathways

  • Technology development outpacing code cycles

  • Lack of field data for emerging applications

  • Difficulty applying legacy standards to new system designs

These issues are particularly important as hydrogen systems move beyond demonstration projects and into commercial deployment. Project developers, equipment manufacturers, code officials, emergency responders, and regulators all need practical guidance that can be applied consistently in the field.

Clearer guidance, improved training, and better coordination among standards bodies can help make existing standards more implementable and can reduce uncertainty for both industry and regulators.

Lifecycle Standards Discussions

The workshop included lifecycle-focused discussions across major hydrogen application areas, including production, storage, carbon capture, distribution, transport, infrastructure, and utilization.

These discussions are important because safety and compliance issues can change significantly depending on where hydrogen is in the value chain. For example, production facilities may raise questions involving hydrogen purity, environmental performance, electrical systems, and pressure equipment. Distribution and transport may raise issues involving pipelines, tube trailers, marine transport, and materials compatibility. Infrastructure discussions may focus on refueling, storage, grid integration, and facility-level safety requirements.

End-use applications introduce additional considerations, including:

  • Mobility safety

  • Stationary power systems

  • Industrial equipment compatibility

  • Chemical production and refining

  • Fuel cell system certification

  • Maintenance and emergency response

Considering these issues across the hydrogen lifecycle can help identify where existing standards are working, where they overlap, and where additional coordination or technical development may be needed.

The Role of Standards Tools and Shared Information

The workshop also highlighted the importance of shared tools and coordination platforms that help stakeholders navigate the hydrogen codes and standards landscape. As hydrogen applications expand, industry members, regulators, code officials, researchers, and project developers need reliable information about which standards exist, where gaps remain, and how different requirements interact.

ANSI’s Hydrogen Standards Landscape and related mapping efforts provide an important foundation for identifying applicable standards across hydrogen technologies and applications. These tools are complemented by ongoing efforts across the hydrogen safety and standards community to maintain current information, coordinate activities, and communicate technical developments.

The Pacific Northwest National Laboratory maintains the H2Tools Portal, including a searchable codes and standards database that allows users to identify relevant documents by application, technology, organization, and subject area. FCHEA is working with Pacific Northwest National Laboratory and other stakeholders to support updates to the database and improve the availability of accurate, current information on hydrogen and fuel cell codes and standards.

The National Hydrogen and Fuel Cell Codes and Standards Coordinating Committee also plays an important role in connecting standards development organizations, federal agencies, national laboratories, industry representatives, and technical experts. Through regular information sharing, the committee helps participants identify overlapping activities, emerging standards needs, opportunities for collaboration, and developments that may affect hydrogen deployment. FCHEA also coordinates the work of this committee.

Publications such as the Hydrogen and Fuel Cell Safety Report provide another channel for sharing this information with a broader audience. The report highlights recent developments in codes, standards, regulations, research, safety practices, and industry implementation, helping technical and policy stakeholders understand how these activities relate to real-world hydrogen deployment.

Together, these resources can support:

  • Identification of applicable codes and standards

  • Standards gap analysis and prioritization

  • Coordination among standards development organizations

  • Regulatory and permitting review

  • Dissemination of safety information and lessons learned

  • Training and education

  • Cross-sector communication

  • Tracking of emerging technical and regulatory developments

As the hydrogen standards landscape becomes more complex, maintaining accurate databases, active coordination forums, and accessible technical publications will be increasingly important. These tools do not replace standards or regulatory requirements, but they can help stakeholders understand the broader landscape, avoid duplication, identify unresolved issues, and apply available information more consistently.

IPHE Report Highlights Hydrogen Certification Differences Shaping International Trade and Market Development

by Mhamed Samet, FCHEA

As hydrogen markets continue to develop across different regions, certification systems are becoming increasingly important for determining how hydrogen and its derivatives are classified, traded, and recognized across borders.

In May 2026, the International Partnership for Hydrogen and Fuel Cells in the Economy (IPHE) released the second edition of its report comparing hydrogen certification mechanisms. The report examines 21 certification schemes and 7 support mechanisms across 11 countries or regions, including schemes used for regulatory compliance, voluntary reporting, and support mechanisms such as tax credits or market incentives. The comparison focuses on four major elements: product attributes, operational setup and procedures, chain of custody models, and registry information technology.

IPHE also hosted a webinar on the report, featuring Margarita Ilinich of Natural Resources Canada and Jan Stelter of NOW GmbH. The webinar covered the report's key findings, differences between certification schemes, implications for international hydrogen trade, and possible pathways toward greater interoperability, including modular approaches and digital product passports.

The report points to a central challenge for the hydrogen industry. Certification systems are expanding, but they are not developing in a fully consistent way.

Certification and Market Recognition

Hydrogen certification schemes are intended to provide information about the attributes of hydrogen or hydrogen derivatives. These attributes may include greenhouse gas emissions, electricity sourcing, production pathway, feedstock, water use, land use, or other environmental and social considerations.

Certification systems can support:

  • Regulatory compliance

  • Voluntary reporting

  • Tax credit eligibility

  • Market access

  • Customer disclosure

  • Cross border trade

  • Investment and procurement decisions

The report found considerable variation between certification schemes. Some schemes are already operating, while others remain under development. Some are intended for compliance markets, while others support voluntary disclosure or incentive programs. According to the report, 75 percent of the schemes and mechanisms reviewed were existing, while 25 percent were still in development.

This variation matters because hydrogen certified under one system may not automatically be recognized under another. As international hydrogen trade grows, differences in certification rules could affect whether hydrogen produced in one country can qualify for incentives, regulatory compliance, or market recognition in another.

Greenhouse Gas Accounting Differences

Greenhouse gas emissions accounting is the most widely tracked product attribute across hydrogen certification schemes. However, the report found that schemes differ in how they calculate emissions, define system boundaries, apply thresholds, and treat production technologies and feedstocks.

Key differences may include:

  • Lifecycle system boundaries

  • Electricity sourcing requirements

  • Temporal matching requirements

  • Geographic correlation rules

  • Allocation methods for co products

  • Treatment of carbon capture

  • Treatment of hydrogen derivatives

  • Production pathway eligibility

The report indicates that differences in greenhouse gas emissions accounting methodologies, thresholds, permissible technologies, feedstocks, and electricity sourcing are expected to have a medium to high impact on tradability.

For industry, this means that a hydrogen producer may need to provide different calculations or datasets depending on the market being served. These differences can increase reporting complexity and make it harder for customers, regulators, and investors to compare hydrogen products consistently.

Chain of Custody and Traceability

The report also identifies chain of custody as a major source of potential trade friction. Chain of custody refers to how hydrogen and certification information are tracked from production through delivery or use.

The report discusses two major models:

  • Mass balance

  • Book and claim

Mass balance generally requires a physical link between the certified product and the supply chain, while book and claim separates the certificate from the physical product. The report notes that these are fundamentally different approaches and that compatibility between the two may be limited where regulatory systems require a physical connection between production and use.

Even when schemes use the same chain of custody model, differences can remain in:

  • Balancing periods

  • Certificate cancellation rules

  • Tracking requirements

  • Mixing and blending provisions

  • Registry practices

  • Physical infrastructure requirements

These details can affect whether certified hydrogen can move between markets without duplicative verification or recertification. The report notes a general trend toward mass balance and recommends that schemes in early stages of development consider mass balance to support compatibility across certification systems, while also recognizing that mass balance requires physical infrastructure capable of supporting certified hydrogen movement.

Operational Procedures and Conformity Assessment

Certification does not depend only on emissions calculations or tracking models. It also depends on the operational setup of the scheme, including the roles of certification bodies, issuing bodies, accreditation bodies, auditors, and registry operators.

The IPHE report found that differences in institutional setup and operational procedures are expected to have a high impact on tradability. Schemes that align with voluntary technical standards for operational setup may be less willing to recognize schemes that do not follow similar procedures.

Operational elements may include:

  • Auditor qualification requirements

  • Verification procedures

  • Certification body accreditation

  • Issuing body responsibilities

  • Registry governance

  • Data reporting requirements

  • Document retention

  • Review and appeals processes

These issues are important because certification systems need to be trusted by regulators, buyers, and trading partners. Even when two schemes use similar emissions thresholds, differences in verification procedures or accreditation requirements can limit mutual recognition.

Digital Product Passports

The report also evaluates digital product passports as a potential tool to improve the exchange of certification information across jurisdictions.

A digital product passport for hydrogen could contain or link to information needed to determine whether a quantity of hydrogen certified under one scheme meets the requirements of another. This could include emissions data, production pathway information, electricity sourcing data, chain of custody information, and certification status.

Potential benefits include:

  • Improved data transparency

  • Easier comparison across schemes

  • Reduced duplicative reporting

  • Support for cross-border trade

  • Better traceability across the value chain

However, the report also notes that digital product passport initiatives remain at an early stage. Information availability is limited, and there are still gaps in understanding how these tools would work in practice. The report suggests that digital passports may help accommodate differences in product attributes, but their ability to support mutual recognition across operational setup and chain of custody models remains limited or uncertain.

A Modular Approach to Interoperability

Rather than assuming that all jurisdictions will adopt a single global certification system, the report recommends a modular approach. Under this model, jurisdictions or scheme owners could agree on common modules for certain certification elements while maintaining jurisdiction specific requirements where needed.

The report identifies greenhouse gas emissions intensity as a logical starting point because it is the most widely considered product attribute across certification schemes. The report also notes that the ISO 19870 standard series, developed through ISO/TC 197/SC 1, could serve as a reference for common greenhouse gas accounting modules.

A modular approach could include:

  • Common greenhouse gas accounting modules

  • Shared data requirements

  • Aligned chain of custody provisions

  • Common operational procedures

  • Recognition of relevant voluntary technical standards

  • Digital tools to communicate certification information

If full methodological alignment is not possible, the report suggests that companies along the hydrogen value chain could provide the data needed to calculate emissions under multiple methodologies. This would not eliminate differences between schemes, but it could reduce duplicative data collection and make cross market comparison more practical.

Looking Ahead

The IPHE report and webinar show that certification will continue to play an important role in hydrogen market development, particularly as hydrogen and hydrogen derivatives begin moving across borders.

Future work is likely to focus on:

  • Improving interoperability between certification schemes

  • Clarifying greenhouse gas accounting methodologies

  • Supporting implementation of ISO 19870 and related standards

  • Aligning operational procedures and verification practices

  • Reducing unnecessary duplication in certification requirements

  • Improving registry and data management systems

  • Developing practical digital product passport tools

  • Supporting traceability across the full hydrogen value chain

The report reinforces that certification is not only a market or policy issue. It is also a practical implementation issue involving data quality, verification, traceability, standards alignment, and regulatory recognition. As hydrogen markets mature, the ability of certification systems to communicate clearly with one another will be important to supporting safe, transparent, and efficient hydrogen trade.

For more information about the IPHE report and webinar, click here.