Assessing fugitive emissions of CH4 from high-pressure gas pipelines in the UK

Abstract

Natural gas pipelines are an important source of fugitive methane emissions in lifecycle greenhouse gas assessments but limited monitoring has taken place of UK pipelines to quantify fugitive emissions. This study investigated methane emissions from the UK high-pressure pipeline system (National Transmission System - NTS) for natural gas pipelines. Mobile surveys of CH emissions were conducted across four areas in the UK, with routes bisecting high-pressure pipelines (with a maximum operating pressure of 85bar) and separate control routes away from the pipelines. A manual survey of soil gas measurements was also conducted along one of the high-pressure pipelines using a tunable diode laser. For the pipeline routes, there were 26 peaks above 2.1ppmv CH at 0.23peaks/km, compared with 12 peaks at 0.11peaks/km on control routes. Three distinct thermogenic emissions were identified on the basis of the isotopic signal from these elevated concentrations with a peak rate of 0.03peaks/km. A further three thermogenic emissions on pipeline routes were associated with pipeline infrastructure. Methane fluxes from control routes were statistically significantly lower than the fluxes measured on pipeline routes, with an overall pipeline flux of 627 (241-1123 interquartile range) tonnes CH/km/yr. Soil gas CH measurements indicated a total flux of 62.6ktCH/yr, which equates to 2.9% of total annual CH4 emissions in the UK. We recommend further monitoring of the UK natural gas pipeline network, with assessments of transmission and distribution stations, and distribution pipelines necessary.

Gas-fired power in the UK: Bridging supply gaps and implications of domestic shale gas exploitation for UK climate change targets

“…This is a lower ratio per mile compared to Phillips et al (2013) observations of 3356 leakages in Boston over 785 miles driven. Boothroyd et al (2018) found leakage rates along the NTS to be of similar magnitude and density to lower end of US distribution leaks (Chamberlain et al, 2016;Gallagher et al, 2015), but note that local distribution leak rates remains unclear. These studies illustrate the need for further review of systemic leakage rates in UK and US cities.…”

“…Both studies found a δ 13 CH4 signature consistent with fossil fuel CH4, rather than biogenic sources. Boothroyd et al (2018) carried out a similar analysis in the UK and found leakage rates along the National Transmissions System (NTS) to be of similar magnitude and density to lower end of US distribution leaks (Chamberlain et al, 2016;Gallagher et al, 2015). However, Boothroyd et al note that local distribution leak rates remain unclear.…”

Compartmentalisation and groundwater–surface water interactions in a prospective shale gas basin: Assessment using variance analysis and multivariate statistics on water quality data

“…The rapid expansion of hydraulic fracturing (fracking) to exploit unconventional shale gas reservoirs in the United States has led to a range of environmental concerns: induced seismicity (Davies, Foulger, Bindley, & Styles, 2013); water usage and contamination (Kondash, Lauer, & Vengosh, 2018; Vengosh, Jackson, Warner, Darrah, & Kondash, 2014; Vengosh, Warner, Jackson, & Darrah, 2013); fugitive methane (CH 4 ) emissions (Boothroyd, Almond, Qassim, Worrall, & Davies, 2016; Boothroyd, Almond, Worrall, Davies, & Davies, 2018); human health effects (Currie, Greenstone, & Meckel, 2017); air quality and noise (Goodman et al, 2016); and surface footprint (Clancy, Worrall, Davies, & Gluyas, 2018). Potential contamination of surface waters and groundwater from spills or subsurface contaminant migration has been a particularly common concern (Vidic, Brantley, Vandenbossche, Yoxtheimer, & Abad, 2013).…”

A Common Risk Classification Concept for Safety Related Gas Leaks and Fugitive Emissions?

“…The way the greenhouse gas emissions are assessed is not straight forward, as many factors are part of the picture [5,6]. It is, however, clear that uncontrolled methane leaks and emissions along the natural gas value chain may drastically reduce the climate benefits of natural gas over other fossil fuels, especially in the short term.When studying fugitive emissions from the UK high-pressure pipeline transport system, that is, up to 85 bar pressure, Boothroyd et al [7] detected both soil and air emissions. They concluded that the loss to the air accumulated to as much as 627 tonnes CH 4 /km/yr (241-1123 tonnes CH 4 /km/yr interquartile range).…”

“…When studying fugitive emissions from the UK high-pressure pipeline transport system, that is, up to 85 bar pressure, Boothroyd et al [7] detected both soil and air emissions. They concluded that the loss to the air accumulated to as much as 627 tonnes CH 4 /km/yr (241-1123 tonnes CH 4 /km/yr interquartile range).…”