MH/T 6138.1-2025 in English

Standard Overview and Development Background

MH/T 6138.1-2025, "Greenhouse Gas Product Carbon Footprint Quantification Methodology and Requirements - Aviation Fuel Part 1: General," is a key industry standard issued by the Civil Aviation Administration of China on August 9, 2025, and will officially come into effect on September 1, 2025. This standard builds on the core principles of national life cycle assessment standards such as GB/T 24040, GB/T 24044, and GB/T 24067, and specifically establishes unified methodological requirements for quantifying the carbon footprint of aviation fuel products.

With the implementation of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) and China's "dual carbon" goals, carbon emissions management in the aviation industry is becoming increasingly stringent. Traditional aviation fuels (such as Jet A-1) and sustainable aviation fuel (SAF) require a unified carbon footprint accounting standard to ensure data comparability and credibility. The formulation of this standard fills the gap in domestic aviation fuel carbon footprint accounting standards and provides a scientific and standardized quantitative basis for the entire aviation fuel industry chain.

Analysis of the core terminology system

Chapter 3 of the standard clarifies the definitions of 21 key terms and constructs a complete conceptual framework for aviation fuel carbon footprint accounting:

Of particular note, the standard clearly distinguishes the treatment of biogenic carbon and fossil carbon. CO2 emissions from biogenic carbon are not included in the product carbon footprint but must be reported separately. This provision is of great significance to the carbon footprint accounting of sustainable aviation fuel (SAF).

Quantification Methodology and Technical Requirements

Functional Unit and Reference Flow

The standard specifies that the functional unit is 1 megajoule (MJ) of heat generated by aviation fuel (based on lower calorific value), and the reference flow is 1 ton (t) of aviation fuel. This design allows the carbon footprints of aviation fuel products with different calorific values to be compared based on equivalent energy output.

Definition of system boundary

The system boundary adopts a "cradle to grave" full life cycle approach, covering the following key unit processes:

Selection and Rejection Criteria

The standard establishes clear selection and rejection criteria: Raw materials and energy consumption that are less than 1% by weight may be discarded, but the cumulative amount shall not exceed 5%; general solid waste that is less than 1% of the total solid waste emission mass may be ignored. However, all toxic and hazardous substances must be included in the accounting scope, reflecting the priority of environmental risk management.

Data Quality Requirements and Evaluation System

Chapter 6 of the standard establishes a complete data quality evaluation framework, ensuring the reliability of carbon footprint data from four dimensions:

Data Quality Dimensions

Completeness: Requires coverage of all greenhouse gas emissions and removals that contribute substantially, and conducts mass and energy balance checks.

Representativeness: Data should be representative in terms of time, geography, and technology. Data from the most recent year should be used, and a production-weighted average should be used for multiple regions and multiple plants.

Accuracy: Primary data should be used first, with secondary data used in order of priority (statistical data > literature data > estimated data).

Traceability: All data must be transparent and traceable. Primary data should provide production statistical records, and secondary data should indicate the source and representativeness.

Data Quality Scoring and Grading

Appendix B provides a detailed data quality scoring table and grading criteria, using a 100-point scoring system:

Carbon Footprint Calculation Methodology

Calculation Formula System

Chapter 7 of the standard provides a complete carbon footprint calculation formula system. The core formula is:

CFP = [Σ(AD×EF×GWP) + Σ(IN×CFP) + ΣR] / (LHV + LHV_co-product)×1000 + ΣDLUC

Where:

• AD is activity data, EF is emission factor, and GWP is global warming potential.
• IN is raw material consumption, CFP is raw material carbon footprint.
• R is greenhouse gas removal, LHV is lower heating value.
• DLUC is carbon emissions caused by direct land use change.

GWP selection criteria.

Appendix C provides detailed GWP reference values, using the latest values from the IPCC Sixth Assessment Report (AR6):

Land Use Change Accounting

For crop feedstocks, the standard requires accounting for carbon emissions caused by direct land use change (DLUC), including:

• Calculation of carbon stock changes (aboveground biomass, belowground biomass, litter, and dead wood)
• Calculation of non-CO2 emissions (biomass combustion, soil mineralization)
• January 2008 is used as the benchmark time point for land use change

Implementation Recommendations and Application Guide

Enterprise Implementation Steps

Aviation fuel production enterprises should follow the following steps to implement this standard:

1. Organizational Preparation: Establish a carbon footprint management team and clarify the division of responsibilities
2. Scope Determination: Define the system boundaries and identify all relevant unit processes
3. Data Collection: Collect primary and secondary data according to the table in Appendix A
4. Calculation and Analysis: Calculate the carbon footprint using the formula provided in the standard
5. Report Preparation: Prepare a product carbon footprint report according to the template in Appendix D
6. Verification and Improvement: Seek third-party verification and continuously improve data quality and emission reduction measures

Key Technical Challenges and Solutions

Industry Application Value

The implementation of this standard is of great value to the low-carbon development of the aviation industry:

• Provide a unified methodology: Ensure the comparability of carbon footprints of different aviation fuel products
• Support emission reduction decision-making: Identify carbon emission hotspots and guide the prioritization of emission reduction measures
• Promote green procurement: Provide a basis for airlines to choose low-carbon fuels
• Align with international requirements: Connect with the methodologies of international mechanisms such as CORSIA
• Promote technological innovation: Encourage the research and development and application of low-carbon aviation fuel technologies

Compliance and Declaration Requirements

Chapters 9 and 10 of the standard specify the specific requirements for product carbon footprint reporting and declaration:

Report Content Requirements

A product carbon footprint report should include the following core content:

• Producer information and product information
• Definition of quantification purpose and scope
• Data source and quality assessment
• Inventory analysis and calculation results
• Assumptions and limitations
• Improvement suggestions and future plans

Declaration of Compliance

If a product carbon footprint declaration is required, the requirements of GB/T 24025 or ISO 14026 should be followed, and the following should be noted:

• The declaration must be based on a complete product carbon footprint study
• Third-party verification is recommended to increase credibility
• The comparison conditions and limitations should be clearly stated in the declaration
• Misleading claims should not be made

This standard, as the foundational standard for aviation fuel carbon footprint accounting, will form a complete standard system together with subsequently released specific fuel type standards (such as MH/T 6138.2), providing solid technical support for the low-carbon transformation of China's aviation industry.