Onshore oil and gas: quantifying whole-site methane emissions and associated uncertainties: summary
Published 28 November 2022
Applies to England
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1. Chief Scientist’s Group report summary
This project investigated methods for quantifying the amount of methane emitted from onshore oil and gas (OOG) sites in England. The findings will allow informed choices to be made on methane quantification approaches for different purposes and show how much certainty can be placed in the measurement results.
1.1 Background
Methane emissions from OOG sites contribute towards the UK’s inventory of methane emissions. Understanding and quantifying such emissions is important when prioritising action to reduce methane emissions. However, there are currently no standard methods for quantifying whole-site methane emissions from OOG sites.
1.2 Approach
We reviewed a wide range of methods for quantifying whole-site emissions in order to select those methods best suited for different types of OOG sites. The most promising methods were selected for a detailed evaluation of the associated uncertainty.
We considered the different sources of uncertainty associated with measuring the methane emissions from the whole of a site and set out recommendations for choosing a measurement technique for different site types and locations.
As well as the uncertainty of the measurement method itself, the project also considered the uncertainty associated with measurement campaigns, emission types, changes over time (temporal variability) and method implementation.
1.3 Results
The methods chosen to consider in detail were plume-based flux recovery (US EPA Other Test Method 33a); component-level measurements; mass balance; fenceline monitoring; and the tracer method.
The tracer method was the preferred approach for methane quantification at most categories of OOG sites in England.
1.4 Conclusions
We found that there is little published data on the accuracy of different measurement methods. To address this, controlled releases should be used to understand the method detection limits and accuracy.
The application of the selected methods should be standardised and implemented by qualified and experienced staff.
1.5 Project details:
This summary relates to information from the following project:
- Report: SC210006/R
- Title: Onshore oil and gas: quantifying whole-site methane emissions and associated uncertainties
- Project manager: Mark Bourn, Chief Scientist’s Group
This project was commissioned by the Environment Agency’s Chief Scientist’s Group, which provides scientific knowledge, tools and techniques to enable us to protect and manage the environment as effectively as possible.
Enquiries: [email protected].
© Environment Agency