by Christian Mikkelsen

July 21, 2026

As governments finalize hydrogen incentives and certification programs around the world, accurately measuring lifecycle greenhouse gas emissions has become increasingly important for project development, investment, and international trade. Hydrogen is often described by color, gray, blue, and green, but these labels are only shorthand. What increasingly determines hydrogen’s value in today’s market is its lifecycle greenhouse gas emissions, or carbon intensity.

Calculating that number is where things get complicated. A growing set of standards, regulations, and certification schemes now governs hydrogen GHG accounting in the United States and internationally. Some are legally required; others are voluntary. Some are finalized and active; others are still being written. Increasingly, carbon intensity accounting is becoming a prerequisite for accessing tax incentives, participating in certification programs, demonstrating compliance with regulatory requirements, and competing in international hydrogen markets. As the hydrogen industry scales and begins trading across borders, the differences between these schemes, and the case for coordinating them, warrant a closer look.

45V and the GREET Model

The clean hydrogen production tax credit established under Section 45V of the Internal Revenue Code is the most consequential U.S. policy specific to hydrogen production. It is a required regulatory framework in the sense that any producer seeking the credit must comply with its rules, though claiming the credit itself remains optional. 45V calculates emissions on a well-to-gate basis using the 45VH2-GREET model, a hydrogen-specific version of the lifecycle analysis tool developed by Argonne National Laboratory and ties the credit value to the resulting carbon intensity score.

Much of the debate around 45V has centered on a methodological question with real economic consequences: how should the emissions associated with grid electricity be counted when that electricity powers an electrolyzer? Proposals requiring strict, hour-by-hour matching between electricity generation and hydrogen production aim to ensure environmental soundness but increase project costs and complexity. More flexible accounting lowers costs but risks crediting hydrogen that isn’t genuinely low carbon. The final rules, issued in early 2025, reflect an attempt to balance these concerns and remain an ongoing illustration of how a single accounting choice can shape which projects get built.

It’s worth noting that 45V stands apart from other federal credits sometimes mentioned alongside it. Section 45Q, which broadly supports carbon capture and storage, and Section 45Z, which applies to transportation fuel production and use, use different methodologies and serve different parts of the energy economy. They intersect hydrogen in places, 45Q is relevant to low-carbon hydrogen projects that capture and store carbon, but they aren’t interchangeable with 45V, and conflating the three risks oversimplifying a landscape that’s already difficult to navigate.

International Approaches

The European Union has taken a different but parallel path. Rather than a tax credit, it has adopted a regulatory framework that establishes both renewable electricity requirements and lifecycle GHG accounting methodologies for renewable and low-carbon hydrogen, primarily through delegated acts under the Renewable Energy Directive, including Delegated Regulation (EU) 2023/1184 and Delegated Regulation (EU) 2023/1185, along with a companion framework for low-carbon hydrogen adopted in July 2025. These frameworks generally require a minimum lifecycle GHG savings threshold of around 70 percent relative to a fossil fuel comparator. Unlike 45V, which centers on a sliding-scale tax credit, the EU framework functions as a regulatory requirement tied to market access.

Alongside that regulatory requirement, voluntary certification schemes such as CertifHy have emerged to provide third-party verification and a tradable proof-of-sustainability system, giving buyers a way to confirm that a given batch of hydrogen meets a recognized standard; schemes operated by ISCC and REDcert received similar recognition from the European Commission in December 2024. Other countries, including Japan and South Korea, are developing their own national certification approaches and carbon intensity thresholds, each reflecting local policy priorities and market structures. The result is a situation in which a producer hoping to export hydrogen internationally may need to demonstrate compliance with several distinct frameworks, some mandatory, some voluntary, some still being finalized, simultaneously.

ISO 19870 and the GHG Protocol

Underneath these policy and certification frameworks sit standard-setting efforts designed to establish a shared scientific foundation. Rather than defining a single, fixed methodology, the ISO 19870 series provides internationally recognized principles and methodologies for determining the GHG emissions associated with hydrogen production, conditioning, and transport, addressing foundational questions such as where the system boundary for a given calculation should begin and end, and how emissions should be attributed when hydrogen is produced alongside other products. The series is evolving: ISO 19870-1, published as a full International Standard, is beginning to replace the original ISO/TS 19870 Technical Specification, with additional parts covering conditioning, transport, and carrier-based pathways such as ammonia still in development. This structure is designed to serve as an important reference point that emerging regulatory and certification frameworks can build on, rather than as a single standard those frameworks must be adopted wholesale.

The Greenhouse Gas Protocol, long the standard reference for corporate emissions reporting, is developing hydrogen-specific guidance intended to help companies report consistently across their supply chains. Unlike 45V or the EU delegated acts, neither the ISO 19870 series nor the GHG Protocol is mandatory on its own. Their value lies in providing a common methodological foundation that policy frameworks can build on, rather than in developing incompatible approaches independently.

Why Alignment Matters

Given how different these frameworks are in purpose, legal status, and geography, it would be unrealistic to expect a single, unified global accounting system to emerge, nor is that necessarily the right goal. A tax credit designed to incentivize U.S. production and a regulatory threshold designed to govern EU market access serve different functions and will likely always look somewhat different from one another.

But the practical costs of leaving these frameworks unaligned are real and already visible. A producer selling into multiple markets may need to run separate carbon intensity calculations for the same facility under 45V’s GREET-based methodology and the EU’s delegated act methodology, even when the underlying emissions are identical, simply because the two frameworks draw system boundaries or count grid electricity differently. Each additional framework can mean a separate audit, a separate set of documentation, and a separate verification body, adding cost and time without necessarily adding environmental rigor. Inconsistent methodologies also make it harder for investors and off takers to compare projects across geographies on a like-for-like basis, since a carbon intensity score calculated one way isn’t automatically comparable to one calculated another way. Left unaddressed, these frictions function as a quiet barrier to international hydrogen trade, discouraging exactly the kind of cross-border project development that a maturing hydrogen economy needs.

What is achievable, and increasingly necessary, is greater alignment, interoperability, and openness across these procedures. That means more precise documentation of how each framework treats core methodological questions, more consistent terminology, and a disposition among regulators and standards bodies to build new frameworks on existing ones rather than starting from scratch. Progress here would reduce duplicate compliance costs for producers, give investors more comparable data across projects and geographies, and make it easier for hydrogen to move across borders as a genuinely tradable commodity.

FCHEA’s Role

FCHEA works with its members, policymakers, and standards bodies to advance practical, science-based, and technology-neutral approaches to hydrogen GHG accounting. Through its Technical & Regulatory Working Group, tax webinars, engagement with external agencies, and participation in national and international standards activities, FCHEA helps track the developing regulatory and standards landscape and works to ensure its members understand both the prospects and the compliance implications as these developments unfold. That includes supporting efforts to improve alignment across methodologies, so that hydrogen produced and certified in one market can be more easily recognized in another.

Looking Ahead

The frameworks regulating hydrogen GHG accounting will continue to evolve over the next several years as 45V implementation matures, the EU’s regulatory requirements take full effect, and international standards bodies update their guidance. These frameworks are unlikely to converge into one single system, but the degree to which they can speak a common language, recognize each other’s methodologies, and reduce unnecessary duplication will shape how efficiently the hydrogen economy can scale, attract investment, and trade across borders in the years ahead.