A recent study from researchers at Princeton University and Colorado State University finds that the current method for estimating methane emissions from offshore oil and gas production in the United Kingdom systematically and severely underestimates emissions.
The study finds that as much as five times more methane is being emitted from oil and gas production in the UK than what the government has reported.
The researchers reached this conclusion by critically evaluating the UK’s current method of calculating methane emissions, suggesting alternative, peer-review based methods and generating revised emission estimates.
Since many other countries use similar methodologies to calculate methane emissions from oil and gas production, this severe underestimation is likely not confined to the UK alone.
It is critical to know when, where and how much methane is emitted from each of its sources in order to prioritize emission reductions. We hope our work will facilitate improved emission estimates and reductions not only from the UK but also from other countries producing methane from oil and gas extraction,
said Denise Mauzerall, a co-author and core faculty member of the Center for Policy Research on Energy and the Environment at Princeton University.
One major source of methane to the atmosphere is the extraction and transport of oil and gas. Countries are obligated to report their greenhouse gas emissions to international bodies such as the United Nations Framework Convention on Climate Change. However, recent studies suggest that the current methods for calculating methane emissions rely on outdated and incomplete information and may not accurately represent actual emissions.
The study focused on methane leakage associated with discovery, extraction, and production of oil and natural gas. These methane emissions are typically calculated by multiplying the activity level of various processes by “emission factors,” which are standard estimates of the methane emissions associated with each activity.
The researchers found that the emissions factors used in the UK’s reporting are either outdated, rely on unpublished or publicly unavailable industry research, or use generic values recommended by the IPCC.
Furthermore, these emission factors are usually “static,” meaning that they are not sensitive to factors such as environmental conditions and management practices which could affect emissions from various processes.
In addition, leakage can occur when the off-shore rigs are idle – an “activity” that does not currently have an associated emission factor.
Noting these shortcomings, the researchers updated and revised estimation techniques for each process, and, wherever possible, used dynamic rather than static emission factor formulations that account for varying environmental conditions.
They also incorporated direct boat-based measurements of methane concentrations around offshore gas platforms in the North Sea collected in summer 2017. These updates resulted in a total methane emission estimate more than five times larger than reported emissions.
Methane emissions from offshore facilities are currently largely uncertain, and because sources on facilities only emit for a short time period, using direct survey methods such as satellite or drones will probably only capture about 25% of the actual emissions
stated Stuart Riddick, lead author and research scientist at Colorado State University
Previous research has shown that reducing leakage across the oil and natural gas supply chain can advance climate and air quality goals while also being economically profitable.
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