This analysis on biogas and biomethane acknowledges that, while these sources are cleaner than fossil fuels, they release more methane than earlier estimates suggested. A study published in One Earth by Imperial College London shows that methane leakage in these supply chains may be higher than previously thought. Even so, when compared with non-renewable options, biogas and biomethane still offer a cleaner energy option, though the findings highlight the need for tighter leak control and more effective repair programs to preserve their green credentials.
Both biogas and biomethane arise from the decomposition of organic matter, including food scraps, animal waste, energy crops, grass, and sewage sludge. They stand as renewable alternatives to natural gas, coal, and oil. Yet researchers identify vulnerabilities in the energy supply chains that deliver these climate-influencing gases and conclude that ongoing efforts are required to reduce methane leaks.
The Intergovernmental Panel on Climate Change’s AR6 report notes that methane traps heat about 27 times more effectively than carbon dioxide over a 100-year period and contributes at least a quarter of global warming.
New Imperial findings indicate that biomethane and biogas supply chains release methane at levels roughly double the previous estimates from the International Energy Agency. The study also shows that 62% of these leaks come from a small subset of plants and equipment within the chain, what researchers describe as “super emitters.” Yet methane releases occur at all stages of the process.
The researchers emphasize that urgent attention is needed to pinpoint and fix methane leaks. Knowing where emissions occur helps manufacturers target corrective actions effectively.
“Poorly designed and managed facilities”
The study’s lead author, a researcher from the Department of Chemical Engineering and the Sustainable Gas Institute at Imperial, Semra Bakkaloğlu, stated that while biomethane and biogas are strong candidates for renewable and clean energy, they can also emit methane. To truly curb the warming impact of energy use, action is required now to reduce emissions. The aim is to keep biogas and biomethane in the energy mix as renewable resources by eliminating methane leaks through the necessary steps.
Compared with the oil and gas sector, the biomethane industry struggles with poorly designed, underinvested production facilities and a lack of modernization, operation, and control. Oil and gas supply chains have long benefited from the scale and resources of large companies, enabling greater investment in leak detection and repair.
In response to the climate crisis, many nations are shifting away from high-carbon fuels such as natural gas, coal, and oil toward biomethane and biogas. While both fuels are composed of CO2 and methane, they emit less of each gas, making them greener energy options overall.
Nevertheless, leaks persist throughout the supply chain, especially in processing plants and long pipelines. This new analysis offers a clearer view of where and when methane is released within the biomethane and biogas systems.
In their review, researchers compiled 51 previously published mobile methane measurements and data from emissions sources across the biomethane and biogas supply chain. They used a Monte Carlo statistical model to quantify total methane emissions, capturing measurements from every stage of the chain and comparing them with off-site field-wide data from earlier studies.
The analysis estimated supply-chain methane emissions up to 343 g CO2e per megajoule with higher heating value, potentially reaching 18.5 megatons of methane per year. By contrast, IEA estimates placed emissions at about 9.1 megatonnes. Although total methane emissions from biogas and biomethane are lower than those from oil and natural gas, the share of methane emitted along the supply chain is much higher for these renewable gases than for oil and gas.
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