UK Government publishes Low Carbon Hydrogen Standard – Version 4
January 20, 2026
From Hydrogen Scotland
The UK Government has published Version 4 of the Low Carbon Hydrogen Standard (LCHS) alongside an updated Data Annex, marking a significant update to the regulatory framework governing low-carbon hydrogen production in the UK.
The revised 186-page standard sets out an updated methodology for calculating lifecycle greenhouse gas emissions from hydrogen production and establishes compliance requirements, including a maximum emissions intensity threshold of 20g CO₂e/MJ (LHV) for hydrogen to qualify as “low carbon”.
LCHS Version 4 will apply to all future hydrogen projects entering into Low Carbon Hydrogen Agreements, including those under upcoming allocation rounds such as HAR2, and will be used for eligibility assessments for future schemes, including HAR3.
According to the UK Government, Version 4 focuses on improving clarity, increasing flexibility for producers, and reducing barriers to demonstrating compliance. Key updates include:
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Expanded eligibility for biomethane supply, including sourcing via the gas grid using a mass balance approach
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A revised process for evidencing Renewable Energy Guarantees of Origin (REGOs), aligned with wider energy sector practices
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New guidance on stored feedstocks and fuels
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The inclusion of asphalt as an additional permissible solid carbon end use
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Simplified material classification for refinery off-gas
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Updated emissions factors, technical parameters, and calculation methodologies in the Data Annex
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New versions of the Hydrogen Emissions Calculator (HEC) reflecting updated pathways and datasets
Applying the LCHS to government-supported hydrogen production, including through the Hydrogen Production Business Model, is intended to ensure that these projects deliver measurable contributions to the UK’s carbon reduction targets.
First introduced in 2022, the Low Carbon Hydrogen Standard continues to be reviewed and updated to remain fit for purpose and aligned with the rapid growth of the hydrogen economy, the Government said.
Link to LCHS Version 4 and supporting documents: https://www.gov.uk/government/
Link to Hydrogen Production Business Model documents: https://www.gov.uk/government/
