CH4 Sentinel: Free Open Source Detection and Measurement of Methane Super Emitters
Created by Ulster University MSc GIS graduate Nicholas Kinsella, CH4 Sentinel is a first of its kind, open-source software tool that detects and quantifies methane (CH₄) emissions using freely available Sentinel-2 satellite imagery.
Most methane quantification methods rely on high-performance computing or commercial radiative-transfer models, which limit accessibility for researchers and practitioners. CH4 Sentinel overcomes these barriers through a machine-learning model that runs effectively on a standard desktop computer, allowing accurate methane assessments to be carried out by anyone with moderate technical skills.
CH4 Sentinel was applied to the Hassi Messaoud oil field in Algeria from 2021 to 2024 to assess methane emissions following the country’s greenhouse-gas reduction commitments introduced in 2021. This produced a multi-year, satellite-based assessment of methane emissions across the entire field, providing a consistent record of super-emitter activity over time. The tool identified and quantified super-emitting point sources exceeding 2 tonnes per hour, using a multi-band, multi-pass technique that enhances plume contrast and minimises false detections in Sentinel-2 Short-Wave Infrared imagery.
To capture the contribution of smaller emissions, Sentinel-5P methane column data were processed using the Integrated Methane Inversion model, developed by the Harvard Atmospheric Modelling Group, to estimate field-level total emissions. Together, these approaches provided a comprehensive view of methane activity, linking individual plumes to wider field-scale trends. This represents the first published multi-year, field-wide, satellite-only assessment of methane emissions, that includes point source super-emitters.
The results showed that super-emitting plumes originated from five point sources in 2021, decreasing to one by 2024. The overall decline in CH₄ emissions was 29,352 tonnes per year, with 86% of that reduction attributed to super-emitters detected by CH4 Sentinel. This decline took place in the context of higher national oil production - indicating a genuine progression in emission reduction.
CH4 Sentinel is the first published tool to demonstrate that reliable and repeatable methane quantification can be achieved entirely with open data and open-source software. Its success has drawn the attention of the European Commission, which requested CH4 Sentinel’s emission data for Hassi Messaud, recognising the tool’s credibility and policy relevance. Since then it has been used by several companies and researchers in consultation with the developer.
This work was presented at SPIE Sensors + Imaging 2025 in Madrid and AGI GeoCymru 2025 in Cardiff. The full paper, Monitoring Methane Emissions at Hassi Messaoud from 2021 to 2024 using CH4 Sentinel and Integrated Methane Inversion, is published in the Proceedings of SPIE. All code and documentation are freely available on GitHub at github.com/Nick-Kinsella/CH4-Sentinel.
Biography
Nicholas Kinsella is a geospatial analyst and remote sensing consultant specialising in satellite-based environmental and industrial monitoring. He earned an MSc with Distinction in Geographic Information Systems from Ulster University, where his thesis on methane emissions at Algeria’s largest oil field won the Ordnance Survey Northern Ireland award and was nominated for the Royal Geographical Society’s prize for outstanding postgraduate research.
Nick has delivered methane emission data for the European Commission and Capterio, and developed geospatial workflows for Space Works Africa and PreZero España using Sentinel-2, Sentinel-5P, and the OpenEO platform. He has presented his work at SPIE Sensors + Imaging 2025 (Madrid) and AGI GeoCymru 2025 (Cardiff), and supports researchers in building satellite-based monitoring workflows.
