MNRE Issues New GHG Emission Guidelines For Water Use In Green Hydrogen Production

The Ministry of New and Renewable Energy (MNRE) has issued detailed guidelines for measuring greenhouse gas (GHG) emissions associated with off-site water drawal and treatment for green hydrogen production in India. Released on June 18, 2026, by Director Prasad A. Chaphekar, the guidelines are part of the Green Hydrogen Certification Scheme of India (GHCI) and are aligned with the international standard ISO 19870:2023.

The new framework aims to establish a uniform approach for calculating emissions within the “Well-to-Gate” boundary of hydrogen production. Under the guidelines, the direct extraction of raw water from natural sources such as rivers, lakes, or seawater is not included in emission calculations. However, emissions arising from water treatment, transportation, and associated energy consumption must be accounted for to ensure accurate carbon intensity assessments.

To address different water sourcing arrangements, MNRE has introduced five operational scenarios. Scenario A applies to hydrogen producers that own and operate captive offsite water treatment facilities. These entities must use primary metered data for emissions calculations, and any renewable energy claims must be supported by valid evidence, such as Load Dispatch Certificates. The use of Renewable Energy Certificates (RECs) for such claims is not permitted.

Scenario B covers water supplied through municipal bodies or state agencies. In such cases, default emission benchmarks will apply unless the utility can provide verified proof that the water supply is powered entirely by renewable energy. Scenario C addresses jointly owned or shared treatment infrastructure, where emissions are allocated among users according to the volume of water consumed.

Scenario D applies to the use of treated wastewater or recycled water. For these projects, the emission boundary begins at the producer’s facility gate, and only the additional energy used for final water polishing and treatment for electrolysis is considered. Scenario E covers hybrid systems that combine multiple water sources, requiring producers to maintain daily records and calculate a weighted average emission factor.

To support implementation, MNRE has specified default emission factors based on data from the Central Electricity Authority (CEA) and international references. The guidelines use an All-India Weighted Average Grid Emission Factor of 0.710 kgCO₂e/kWh and a Transmission and Distribution loss factor of 17.63%. Based on these assumptions, default emission factors are set at 3.017 kgCO₂e/m³ for seawater desalination, 0.603 kgCO₂e/m³ for municipal surface water treatment, and 0.388 kgCO₂e/m³ for recycled water polishing.

The guidelines also state that chemical inputs used in treatment processes can generally be excluded unless their contribution exceeds 0.02 kgCO₂e per kilogram of hydrogen produced. In addition, all critical metering equipment must undergo annual calibration by NABL-accredited laboratories.

For implementation, newly commissioned facilities have been given 90 days to establish monitoring systems, while existing plants have up to 180 days to achieve compliance. In the event of metering failures or force majeure situations, producers must notify verification agencies promptly, and conservative benchmark values will be applied until normal monitoring resumes. The ministry said these measures are intended to strengthen transparency, consistency, and credibility within India’s green hydrogen certification framework.