Controlled-Release Experiment to Optimize Emission Quantification of H₂ Point Sources

Area of Science:

• Atmospheric Chemistry
• Climate Science
• Environmental Monitoring

Background:

• The global energy transition is projected to increase atmospheric hydrogen (H₂) concentrations.
• Fugitive H₂ emissions act as an indirect greenhouse gas, impacting methane and ozone levels.
• Previous measurement techniques lacked the sensitivity to detect climate-relevant H₂ emissions.

Purpose of the Study:

• To optimize a sampling and emission estimation method for fugitive hydrogen.
• To investigate the impact of sampling conditions on emission quantification accuracy.
• To demonstrate a versatile and accessible method for measuring hydrogen emissions.

Main Methods:

• Utilized a multiplatform active AirCore sampler with a high-resolution Gas Chromatography-Photoionization Detector (GC-PDHID) system.
• Conducted controlled hydrogen release experiments using an 8 kW electrolyzer.
• Analyzed 14 downwind profiles from UAV and ground-based sampling to derive emission rates.

Main Results:

• Achieved simultaneous measurement of H₂ (±2 ppb), CH₄ (±0.5 ppb), and CO₂ (±0.3 ppm).
• Derived a weighted mean hydrogen emission rate of 0.94 ± 0.06 m³ h^-1.
• Confirmed that established methane measurement strategies are transferable to hydrogen point sources.

Conclusions:

• The developed method accurately quantifies hydrogen emissions under various sampling conditions.
• This research provides a crucial tool for monitoring and mitigating climate impacts from hydrogen.
• The findings support the safe and sustainable scale-up of hydrogen energy.