The systematic review synthesised 28 peer-reviewed life-cycle assessment studies published from 2015 to 2025. It compared direct combustion, combined heat and power, biomethane upgrading, transport use and carbon capture and utilisation. Results were standardised to one megajoule of useful energy and assessed across climate, eutrophication, acidification, particulate matter and resource-use indicators.
Key findings
- Industrial biomethane and CCU pathways showed the strongest overall performance, whereas household direct combustion had the highest burdens because of methane leakage, uncontrolled emissions and incomplete combustion. Near-term gains most consistently came from leakage control, improved digestate management and incremental upgrading; large CCU remains constrained by infrastructure, hydrogen and cost.
Why this matters globally
The global message is that “biogas” should not be treated as an automatic sustainability label. Policy must specify feedstock, scale, leakage control and digestate management, because climate benefits in one stage can be offset by pollution or resource burdens elsewhere.
Thai researcher contribution
Mahidol University-affiliated authors Kinga Biró, T. Buadit and C. Rattanapan contributed to the synthesis. Thailand and Vietnam were used as policy application contexts for assessing transferability and feasibility in Southeast Asia.
Limitations to consider
Source LCAs differed in system boundaries, feedstocks, technologies, data quality and energy assumptions. Normalisation improves comparability but cannot remove all heterogeneity. Evidence is sparse for some pathways, and global synthesis should not replace site-specific assessment before investment.