Monthly Roundup: Energy and Heat Standards from September 2025

Looking back at September 2025, Energy and Heat standards saw a notable surge in publications addressing both advanced technological systems and foundational measurement techniques. Five significant standards were published, spanning the breadth of energy generation, fuel characterization, decarbonized mobility, critical safety in nuclear effluents, and specialized steam generation for healthcare applications. For industry professionals across technical, compliance, procurement, and research roles, this overview provides not just a summary of these documents but also a lens into the growing importance of harmonization, digital procedures, and sustainability in the sector.

Monthly Overview: September 2025

September 2025 was characterized by a distinctive blend of innovation and standardization maturity within Energy and Heat. The month's batch of standards included updated technical methodologies for photovoltaic power validation, robust measurement protocols for solid and gaseous fuels, and new or revised requirements influencing safety and sustainability across energy sub-domains.

Key themes observed:

• Holistic decarbonization: Standards focusing on hydrogen fuel systems for rail and power performance in photovoltaics highlighted a systemic push towards greener infrastructure.
• Refined measurement techniques: From pellet sizing in solid biofuels to radiological analysis in nuclear effluents, measurement precision was a dominant motif.
• Specialization and safety: Steam boilers for health-sector sterilization and advanced hydrogen handling showcased the need for tailored requirements in high-stakes applications.

Relative to previous publication cycles, September 2025 brought a more integrative and cross-disciplinary approach, reflecting how Energy and Heat is aligning itself with global sustainability targets, regulatory reporting, and operational excellence.

Standards Published This Month

IEC TS 61724-2:2025 - Photovoltaic System Performance Index and Capacity Evaluation

Photovoltaic system performance – Part 2: Power performance index and capacity evaluation method

This second edition defines the test methodology for determining the Power Performance Index (PPI) of grid-connected PV systems, including the latest practices for bifacial modules and unconstrained operation periods. The standard is essential for contractors, operators, and EPC companies delivering or taking over large PV installations, especially when contractual guarantees are tied to system performance. The test, typically conducted over 3–5 days during optimal conditions, compares real output to modeled expectations using up-to-date software and hardware, clarifies the test boundary, documents all test elections, and mandates data filtering for accuracy. Notably, this revision simplifies result calculations, adapts to high DC:AC ratios (addressing clipping/curtailment), and supports evolving PV technologies.

Key highlights:

• Fully incorporates bifacial PV and latest modeling approaches
• Allows short, efficient performance testing for commissioning
• Streamlines data filtering and reporting procedures

Access the full standard:View IEC TS 61724-2:2025 on iTeh Standards

ISO 17829:2025 - Solid Biofuels Pellet Dimension Characterization

Solid biofuels – Determination of length and diameter of pellets

ISO 17829:2025 provides a harmonized methodology for measuring the length and diameter distributions of biomass pellets, integrating updates such as fractions below 10 mm and above 40 mm, and supporting both manual and automated equipment. Especially relevant for pellet producers, quality assurance labs, and solid biofuel users, adherence ensures that pellets conform to design tolerances critical for combustion safety, bulk density estimation, handling, and feeding system operation. This edition reflects feedback from the field, extending sample preparation guidance, defining pellet length, and describing new procedures. It supports compliance with ISO 17225 fuel grading and underpins reliable fuel supply chains for the growing bioenergy sector.

Key highlights:

• Expanded scope to standardized pellet length fractions >40mm & <10mm
• Dual methods: manual (calliper/measuring block) and automated sizing
• Enhanced reporting for supply chain and combustion system compatibility

Access the full standard:View ISO 17829:2025 on iTeh Standards

FprEN IEC 63341-2:2025 - Hydrogen Fuel System for Railway Rolling Stock

Railway applications – Hydrogen and fuel cell systems for rolling stock – Part 2: Hydrogen fuel system

FprEN IEC 63341-2:2025 addresses the technical requirements for on-board hydrogen storage and handling systems that power fuel cell rail vehicles. Covering compressed gaseous hydrogen only, the standard sets comprehensive criteria for interfaces, environmental constraints, design, performance, and particularly for system safety—including environmental risks, mechanical integration, fire protection, testing regimes, and marking. Key target users are rolling stock manufacturers, hydrogen system integrators, and operators investing in decarbonized rail. The document defines how HFS module interfaces connect safely with fuel cells and refueling stations, stipulates reliability and RAMS criteria, and provides validation/testing protocols.

Key highlights:

• Strict environmental and safety requirements for on-board H2 storage
• Detailed interface and test validation guidance
• Core standard for enabling green hydrogen-powered train adoption

Access the full standard:View FprEN IEC 63341-2:2025 on iTeh Standards

EN 14222:2021+A1:2025 - Stainless Steel Steam Boilers for Sterilizers

Stainless steel steam boilers

EN 14222:2021+A1:2025 specifies requirements for electrically heated, stainless steel steam boilers used in the generation of steam for sterilizers and disinfectors, commonly found in healthcare, laboratory, and clean processing environments. With a scope limited to boilers employing immersion heaters, and defined by maximum pressure and volume parameters, the standard ensures that such equipment meets contemporary safety, material, and design standards—including alignment with the EU Pressure Equipment Directive (PED) and cross-references to EN 285 for large sterilizers. Notable updates in this amendment include enhanced limiting device and safety circuit requirements, revised terminology, and new compliance obligations for marking, inspection, and operation. Stakeholders include OEMs, medical/hospital engineers, and regulators.

Key highlights:

• State-of-the-art safety and control features for healthcare steam boilers
• Full compliance alignment with MED and PED requirements
• Specific focus on equipment used for sterilization and disinfection

Access the full standard:View EN 14222:2021+A1:2025 on iTeh Standards

ISO 20041-2:2025 - Tritium and Carbon-14 Measurement in Nuclear Gaseous Effluents

Tritium and carbon-14 activity in gaseous effluents and gas discharges of nuclear installations – Part 2: Determination of tritium and carbon-14 activities sampled by bubbling technique

ISO 20041-2:2025 offers authoritative procedures for quantifying tritium and carbon-14 released in the gaseous effluents during both the operation and decommissioning of nuclear installations. Addressed to nuclear operators, radiological protection professionals, and environmental assessment agencies, the standard details sampling by bubbling technique, analysis via liquid scintillation counting, and calculation of discharge activities for accountability and regulatory reporting. This method ensures representative, accurate, and reproducible activity determinations essential for regulatory compliance and public safety, especially as global scrutiny on nuclear sector emissions increases.

Key highlights:

• Precise methodologies for HTO, HT/TT, 14CO2, 14CO, CH3T, and 14CH4 measurement
• Includes guidance for uncertainty and detection limit determination
• Integral tool for environmental monitoring and regulatory submissions

Access the full standard:View ISO 20041-2:2025 on iTeh Standards

Common Themes and Industry Trends

A retrospective analysis of September 2025’s Energy and Heat standards reveals several converging patterns:

• Decarbonization and Sustainability: The escalation of hydrogen applications in rolling stock and the push for high-efficiency photovoltaics and robust biofuels infrastructure are emblematic of an industry moving toward net-zero targets and supporting global energy transitions.
• Measurement as Foundation: Rigorous, harmonized dimensioning (biomass pellets) and effluent characterization (nuclear facilities) standards underscore the sector’s prioritization of metrology, traceability, and analytics for everything from combustion efficiency to radiological safety.
• Operational Safety and Maturity: Requirements for robust equipment design, redundant safety systems, and codified reporting—such as in steam boilers for sterilization and hydrogen storage for trains—reflect an ever-sharpening focus on mitigating operational risk and social license.
• Digitalization and Flexibility: Emphasis on modern modeling tools (PV power performance), data documentation, and adaptability to evolving technologies and use cases across all standards reinforces the value of digital competence and agile compliance frameworks.

Energy sectors received nearly equal attention, but green mobility (hydrogen trains) and healthcare sterilization (steam boilers) stand out as emergent focal points directly responding to regulatory shifts and public demand for resilient, sustainable infrastructure.

Compliance and Implementation Considerations

For organizations impacted by these standards, a proactive compliance and implementation strategy is key:

• Gap Analysis and Training: Review existing procedures, instrumentation, and reporting against new/updated requirements (especially for PV performance, pellet grading, and hydrogen system integration) and schedule targeted upskilling sessions.
• Documentation and Traceability: Leverage standardized templates and digital systems for test elections (IEC TS 61724-2), sample logging (ISO 17829), and test reporting (ISO 20041-2) to ensure audit-readiness and regulatory alignment.
• Prioritization and Resourcing: Focus near-term efforts on standards with the most direct operational or contractual impact—e.g., new hydrogen train deployments, hospital steam systems, or PV plant commissioning—while scheduling implementation for measurement protocols within annual review cycles.
• Leverage iTeh Resources: Access the full text and implementation guides via iTeh Standards, and consider supplementary training materials or consulting services for complex roll-outs.
• Timeline Considerations: While some standards provide for immediate adoption (voluntary), others may have regulatory compliance dates; consult with your internal compliance officer and national authorities.

Conclusion: Key Takeaways from September 2025

September 2025 offered a rich cross-section of standards that will shape the Energy and Heat sector for years to come. Notable highlights include:

• The definitive shift to digital and model-driven verification in solar performance (IEC TS 61724-2:2025)
• Advanced safety and interface requirements bringing hydrogen rail closer to mainstream adoption (FprEN IEC 63341-2:2025)
• Detailed measurement protocols elevating the quality of biofuel supply chains and nuclear environmental monitoring (ISO 17829:2025, ISO 20041-2:2025)
• Harmonization of safety and operational best practices for specialized steam generation (EN 14222:2021+A1:2025)

Professionals in the sector are advised to:

1. Stay attuned to these harmonized requirements through ongoing standards surveillance
2. Integrate updated methodologies and data requirements into QMS and compliance process flows
3. Reassess investment and procurement plans to ensure compatibility with the evolving regulatory direction

Ensuring detailed familiarity with these new standards will be a competitive and regulatory advantage. For comprehensive access, technical downloads, and ongoing updates, visit iTeh Standards and explore the full standards for practical implementation in your organization.