A six-day methane gas release at Cuadrilla’s fracking site near Blackpool had the same carbon footprint as 142 flights from London to New York, new research has concluded.
A monitoring station, installed by researchers from Manchester University, detected the methane, a powerful greenhouse gas, after it was emitted from the site at Preston New Road.
Analysis showed the methane had been released, unburnt, through the flare stack, from 11-16 January 2019. The researchers estimated about 4.2 tonnes had been emitted.
The release happened during a nitrogen lift operation. This pumped nitrogen into the PNR1z well to unload unwanted fluid and improve gas flow after fracking in October-December 2018.
Cuadrilla confirmed that the flare failed to light and a mixture of methane and nitrogen was vented, unburnt, into the atmosphere.
The Manchester study, reported this week in the Journal of the Air and Waste Management Association, claimed to be the first estimate of methane emissions during a nitrogen lift process for gas extraction.
It said the 4.2 tonnes of methane equated to 143 tonnes of carbon dioxide equivalent, assuming the usual 100-year time period to measure global warming potential (GWP100 value).
The study said:
“The GWP100 value is equivalent to the carbon footprint of 516 MWh of electricity consumed from the UK National Grid: the annual electricity demand of 166 households. Alternatively, equivalence can be drawn with 142 London–New York flights.”
The leader of the project, Professor Grant Allen, professor of atmospheric physics at Manchester University, said:
“Our work shows that atmospheric monitoring of shale gas activity is crucial to meaningfully assess any role that the industry may have in the UK’s future energy mix and whether it can (or cannot) be consistent with the UK’s stated aim of achieving net-zero carbon emissions by 2050.
“This work informs that debate and provides new data on emissions from well-clearing activities that must be captured in industry life cycle assessments, and should be used to inform regulatory oversight and industrial practices surrounding venting activities such as the event quantified here. Such emissions should be avoided wherever possible.”
Dr Jacob Shaw, research associate at Manchester and lead author of the paper, said:
“The dangerous consequences of global warming are now beginning to become evident. Routine monitoring and scrutiny of the fossil fuel industry is crucial if we are to curb impacts, and also if we are to meet the UK Government’s Net Zero targets.”
The study said estimates of methane emissions in the exploratory phases of fracking and nitrogen lift operations had not previously been available for environmental impact assessments.
The emission rates associated with well development, well-unloading, and well-stimulation activities were under-represented, it said, and could be a large proportion of a shale well’s lifecycle emissions.
“the UK Government should consider using Reduced Emission Completion procedures to capture flowback emissions from well-unloading and flowback operations, should onshore shale gas extraction via hydraulic fracturing continue in the future.”
The researchers identified the methane emissions at Preston New Road by comparing monitoring data with two years of baseline measurements. They took into account variability due to season and wind direction.
They used three different methods to estimate the methane release rate. They said the peak release rate for methane during January 2019 was estimated at about 70 grams per second, with an average over the whole week of 16 grams per second.
DrillOrDrop reported last year that the British Geological Survey had identified several peaks in methane concentrations at Preston New Road in mid-January 2019, at about 400% above typical levels. At the time, Cuadrilla said there had been three short spikes. But it did not respond to our request for information about the volume of the methane releases.
In May 2019, the Environment Agency (EA) released information that it had warned Cuadrilla about venting methane at Preston New Road. The EA also recorded three breaches of the site’s environmental permit and estimated 2.7-6.8 tonnes of methane had been vented during nitrogen lifting.
At the time, the permit prohibited venting unburned methane “except where necessary for safety reasons”. The EA said there were four reports of methane above the external notification threshold of 7.1 parts per million (ppm) and two reports above the internal threshold of 5.0 ppm.
In October 2019, after regulators suspended fracking at Preston New Road, Cuadrilla was granted permission to use nitrogen lifting. The EA accepted that the process may “may result in the release of uncombusted formation natural gas (which is principally methane), known as venting.”
That month, a study for the EA concluded that emissions from flares could be underestimated because not all the methane would be burnt, particularly when gas flow was low.