en.Wedoany.com Reported - The Ministry of New and Renewable Energy (MNRE) of India has released a guideline document on accounting for water-related emissions in green hydrogen production, aiming to provide a standardized accounting method for water consumption and treatment emissions under the country's Green Hydrogen Certification (GHCI) scheme. The guidelines introduce five distinct "scenarios" to cover various water source models in India: Scenario A (self-built off-site treatment), where emissions are calculated using primary energy consumption data; Scenario B (national agency or municipal water supply), using standard, predefined baseline emission factors for surface water or groundwater; Scenario C (co-owned infrastructure), where emissions are allocated based on the hydrogen producer's share of total water volume; Scenario D (recycled/tertiary water), calculating emissions only for the final "polishing" treatment step; and Scenario E (mixed water supply), calculating a weighted average emission factor for the entire mixed water source.

For cases where primary data is unavailable, the guidelines specify default baseline emission factors (in kgCO₂e/m³): municipal surface water 0.603, municipal groundwater 0.862, seawater desalination 3.017, brackish water reverse osmosis 1.293, and recycled water polishing 0.388. A key component of the document is Formula G-8, which calculates how these water-related emissions contribute to the overall carbon intensity of hydrogen (in kgCO₂e/kgH₂), typically adding a small (e.g., 6-30 gCO₂e/kgH₂) but mandatory component to the total greenhouse gas footprint.

Serving as both regulatory and operational directives for the industry, the guidelines outline transition provisions for new and existing plants (a 180-day compliance buffer for existing plants), metering failure protocols, force majeure handling, and verification requirements. These guidelines are regulatory in nature and mandatory for all producers seeking GHCI certification, serving as a direct prerequisite for selling certified "green hydrogen" in India. By creating a standardized method for accounting for water treatment emissions and operational energy costs, the guidelines provide clarity for project financing.

The guidelines indicate that the choice of water source has a direct and quantifiable impact on the final carbon footprint of hydrogen. Enterprises should prioritize water sources with the lowest possible emission factors; surface water (0.603 kgCO₂e/m³) and recycled water (0.388 kgCO₂e/m³) are significantly better in carbon terms than desalinated seawater (3.017 kgCO₂e/m³), which may influence project siting and design. For producers using their own treatment plants, the guidelines allow the use of primary data to demonstrate lower specific energy consumption (SEC) than the baseline, creating a direct business incentive for companies to invest in efficient treatment technologies (e.g., energy recovery devices, high-efficiency pumps) to reduce overall carbon intensity. For water supply systems under certain scenarios, an exemption pathway exists if they are powered by 100% renewable energy; water suppliers that can ensure or provide 100% renewable energy may apply for a lower emission factor.

The guidelines provide a simplified compliance pathway for municipal water use through fixed baselines, reducing the need for complex on-site metering. Simultaneously, they offer a clear, auditable framework for ensuring compliance, reducing regulatory risk for producers. There is a clear 180-day deadline for compliance for existing plants, with stringent requirements for metering infrastructure. Delays in compliance, metering failures, or non-disclosure may result in the application of the "highest baseline," significantly increasing the declared emission factor. Although water-related emissions constitute only a small fraction of the total greenhouse gas intensity—for example, approximately 0.5% to 5% of the 2 kgCO₂e/kgH₂ threshold—every gram counts in the race for the lowest carbon intensity, and failure to account correctly could prevent producers from obtaining certification.

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