Even though they are better for the environment, biogas and biomethane leak more than twice as much methane as was previously believed, according to a new Imperial investigation.
Although biogas and biomethane continue to be more environmentally friendly than non-renewable alternatives, the researchers urge enhanced monitoring and leak repair to ensure that biogas and biomethane maintain their reputation as environmentally friendly fuels.
The breakdown of organic materials like food, animal waste, energy crops, grass, or sewage sludge results in the production of biomethane and biogas, which are renewable alternatives to natural gas, coal, and oil.
A greater effort should be made to limit methane leakage, according to researchers at Imperial College London who have highlighted possible hazards in the energy supply chains for these climate-friendly gases.
According to the Intergovernmental Panel on Climate Change’s AR6 report, methane retains at least a quarter of the heat that causes global warming, around 27 times more heat than carbon dioxide (CO2).
According to a recent Imperial study that was just published in the One Earth journal, methane emissions from biomethane and biogas supply chains are more than twice as high as what the International Energy Agency (IEA) had previously estimated.
Although methane was discovered to be leaked at every stage, it also reveals that 62% of these leaks were concentrated in a limited number of facilities and pieces of equipment inside the chain, which they refer to as “super-emitters.”
The majority of the methane leaks, according to the researchers, need to be fixed immediately, and production units will benefit from knowing where they are most frequently occurring. Lead author of the study Dr. Semra Bakkaloglu, of Imperial’s Department of Chemical Engineering and Sustainable Gas Institute, said:
“Biomethane and biogas are great candidates for renewable and clean energy sources, but they can also emit methane. For them to really help mitigate the warming effects of energy use, we must act urgently to reduce their emissions.”
“We want to encourage the continued use of biogas and biomethane as a renewable resource by taking the necessary actions to tackle methane emissions.”
To prevent biogas methane emissions negating the overall benefits of biogas use, urgent attention is needed including continuous monitoring of biogas supply chains. We believe that with the proper detection, measurement, and repair techniques, all emissions can be avoided. We need better regulations, continuous emission measurements, and close collaboration with biogas plant operators in order to address methane emissions and meet Paris Agreement targets.
Dr. Semra Bakkaloglu
In comparison to the oil and gas sector, the biomethane sector, according to the researchers, is plagued by poorly planned and managed production facilities as well as a lack of funding for modernization, operation, and monitoring.
Large corporations with abundant resources have historically controlled the majority of the oil and natural gas supply chains, allowing them to devote more resources to leak detection and repair.
What is biomethane and biogas?
Many nations are switching to biomethane and biogas in place of energy sources that release a lot of carbon dioxide, like natural gas, coal, and oil, in response to the climate problem.
Although biomethane and biogas are produced from a mixture of CO2 and methane, they release fewer of both gases, making them cleaner energy options.
However, these alternative fuels continue to leak methane all the way up their supply chains, from long pipelines to processing plants. We now have a more complete picture of where, when, and how much methane is released from the supply of biomethane and biogas thanks to this new investigation.
Analysing emissions
The researchers examined site data from emission sources along the biomethane and biogas supply chain, as well as data from 51 previously published studies on mobile methane measurements. Using an analysis of the data and a statistical technique known as Monte Carlo, they determined the total methane emissions.
They were therefore able to compare the off-site emissions reported from whole-site measurements in previously published research with all measurements of the whole supply chain emissions at each stage of the chain.
They discovered that the supply chains can emit up to 343 g of CO2-equivalent methane for every additional megajoule of heating, which could be responsible for 18.5 megatonnes of methane annually. Only 9.1 megatonnes of emissions were estimated by the IEA for 2021.
Although the overall methane emissions from biogas and biomethane are lower than those from natural gas and oil, the quantity of methane released from their supply chains as a percentage of total gas production is substantially higher than for gas and oil.
The information is presented in “CO2 equivalents,” a unit of measurement that allows comparison of emissions throughout the oil and natural gas supply chain without affecting downstream activities. We may compare the potential for global warming of various greenhouse gas emissions from diverse research thanks to this unit.
The researchers determined that intermittent emissions patterns, which make them more difficult to measure, poor utilisation of process equipment, and ineffective operations and maintenance procedures are to blame for the leakiness of supply chains.
The researchers claim that continuous monitoring is necessary to identify intermittent emission patterns or unforeseen leakage from supply chains because super-emitters are unlikely to remain consistent over time.
Dr. Bakkaloglu said: “To prevent biogas methane emissions negating the overall benefits of biogas use, urgent attention is needed including continuous monitoring of biogas supply chains. We believe that with the proper detection, measurement, and repair techniques, all emissions can be avoided. We need better regulations, continuous emission measurements, and close collaboration with biogas plant operators in order to address methane emissions and meet Paris Agreement targets.”
“Given the growth in biomethane due to national decarbonisation strategies, urgent efforts are needed for the biomethane supply chain to address not only methane emissions but also the sustainability of biomethane.”
Co-author Dr. Jasmin Cooper, also of the Department of Chemical Engineering, said:
“Addressing the fundamental design issues and investment problems within the biofuel and methane industry would be a good starting point for stopping these leaks and preventing more from arising.”
In order to better understand how to eliminate super-emitters utilizing the greatest technology now available, researchers are increasingly concentrating on supply chains. The Sustainable Gas Institute at Imperial financed this study.
