PtX GHG Methodologies Guidebook
Green hydrogen and Power-to-X products are entering international markets, but there is no single way to calculate their greenhouse gas (GHG) footprint. More than 35 GHG emissions calculation methodologies and related frameworks have emerged, differing in system boundaries, treatment of electricity and feedstocks, allocation rules, default values, emissions thresholds and verification requirements.
This guidebook maps and compares the methodologies most relevant to hydrogen and Power-to-X (PtX) producers serving international markets.
It helps producers understand which methodology applies to a specific product and target market and how the calculation under these methodologies may affect reported emissions, project design, electricity sourcing strategies and data needs.
The guidebook examines major methodologies in four areas:
- Compliance markets: EU RFNBO, EU CBAM, and schemes in India, South Korea and Japan
- Sectorial frameworks: ICAO CORSIA for aviation and IMO for maritime shipping
- Corporate commitments: ISO 19870, ISO 14067 and the Green Hydrogen Standard
- Carbon credit generation: UNFCCC Article 6.4, Verra VCS, Gold Standard and the Global Carbon Council
The guidebook demonstrates that GHG accounting is not merely a reporting task. For hydrogen and PtX projects, the selected methodology determines market access, commercial viability and the credibility of a product’s emission savings claim. It is accompanied by carbon intensity calculators for hydrogen, ammonia and e-fuels under the EU CBAM, EU RFNBO, the Indian GHCI, the South Korean CHCS, the IMO and the ICAO CORSIA methodologies.
Calculation Tools
You can find the accompanying GHG emissions calculators for hydrogen, ammonia, and e-fuels here:
Watch: Guidebook and Calculators Walkthrough
To get an introduction to the guidebook and calculators, watch the launch webinar here:
The webinar was recorded on November 3, 2026.
From a Policymaker's Perspective
If you are a policymaker interested in standards and GHG emissions accounting methodologies for Power-to-X products, take a look at this webinar, which discusses the topic and presents policy recommendations to support domestic industries in complying.
