Oil and Gas Groups Under Pressure to Plug Leaks
Boom
times for US oil and gas have shone a new spotlight on an old problem: leaks of
methane, a powerful greenhouse gas.
Persistent
leakage of its main constituent undercuts the claim that natural gas helps
economies shift away from more polluting energy sources.
While
US energy-related carbon dioxide emissions have declined as natural gas
displaces coal at power stations, methane emitted by the oil and gas sectors
has not.
Aside
from the climate danger, oil and gas companies say they would rather make money
by selling it.
Quantifying
volumes is difficult, however. As US energy industry and regulators attempt to
rein in methane emissions, they are grappling over the best ways to measure
them.
The
most notorious recent leak took place over four months in 2015-16, when about
5bn cubic feet of gas seeped from the Aliso Canyon storage site in Los Angeles.
But many leaks of the colourless, odourless gas are dispersed and sporadic,
evading detection.
Official
inventory data from the Environmental Protection Agency show that between 2005
and 2017, methane emissions from US petroleum systems climbed 2.5 per cent to
1.5m tonnes, led by growth from upstream producers. Emissions from natural gas
systems declined 3.4 per cent to 6.6m tonnes over the same period.
The
EPA data are based on a “bottom up” approach of estimating emissions at
individual sites and extrapolating them to the whole country — a method with
limitations, according to a 2018 government-sponsored study.
Guidelines
for checking inventories have not been updated since 2006 — before fracking
transformed US oil and gas production. Bottom-up measurements are taken only
periodically, “so if the emissions occur in a burst at midnight, no one is
there to measure it, you haven’t captured it and you come to a false sense of
the emissions reading”, said James White, a professor of geological sciences at
the University of Colorado Boulder who chaired the study.
Another
“top down” approach uses sensors on aircraft, satellites and towers to estimate
methane levels in the atmosphere. But the network of sites is “sparse”,
according to the 2018 study, and it can be difficult to trace emissions’
sources.
Timing
is also a drawback of atmospheric measurement. Leaks can rise and fall with gas
volumes, for example when heating demand is high during a cold snap. “One thing
that can be problematic about the ‘top down’ approach is that you’re assuming
operations are steady-state and constant. That’s just not the way that we
necessarily operate,” said Sandra Snyder, senior regulatory attorney at the
Interstate Natural Gas Association of America, a pipeline industry group.
Recent
studies have shown “conflicting results” on the trend of methane emissions from
oil and gas operations in the US, according to a 2019 paper by scientists at
the National Oceanic and Atmospheric Administration, which itself found a
“modest increase”. But another paper co-ordinated by the Environmental Defense
Fund, a campaign group, found methane emissions from the oil and gas industry
were at least 60 per cent higher than government statistics suggested.
Under
President Donald Trump, the EPA has sought to loosen standards for methane
leaks from the oil and gas industry. Among its proposals, bigger oil and gas
wells would need to be monitored once instead of twice a year — a plan
supported by many in the industry.
Environmental
groups oppose the change. Mark Brownstein of the EDF said a large portion of
emissions was coming from a handful of sources, often from equipment failure or
worker error. With more frequent inspections, “you’re constantly on the lookout
for situations where the equipment is not operating as designed”.
Technology
to find leaks has improved. Optical imaging cameras that detect traces of gas
can be mounted on drones, for example, reducing the cost of visiting far-flung
well sites.
The
industry has announced voluntary measures to address methane leaks. The Oil and
Gas Climate Initiative, an international group of upstream producers whose US
members include Chevron, Exxon Mobil and Occidental Petroleum, in September
committed to cut methane lost to the atmosphere below 0.25 per cent of gas sold
by 2025, down from 0.32 per cent in 2017.
The
One Future Coalition, a group of US natural gas companies, has outlined a goal
of cutting methane emissions to less than 1 per cent of gross natural gas
production and delivery, which the group contends would provide “clear and
immediate [greenhouse gas] reduction benefits as compared to any other fossil
fuel in any other application”.
The
Environmental Partnership, formed by industry lobby group the American
Petroleum Institute, aims to cut methane through technical fixes such as
replacing control valves powered by escaping gas.
Christopher
Smith, a senior vice-president at Cheniere Energy, the biggest US liquefied
natural gas exporter, said stricter regulations and better practices could help
the country compete in world energy markets.
“It’s part of our value proposition, part of our business model, to be able to differentiate natural gas coming from the United States.”