Gas flares far less efficient, causing greater climate impact: study

Flaring — the burning of unwanted natural gas from oil and gas wells — is spewing five times more of the potent greenhouse gas methane into the atmosphere over the United States than previously thought, according to a study released Thursday.

As a result, a much greater impact on climate changeand the warming potential between the claimed and actual efficiency of flaring in the United States is equivalent to putting 2.9 million more cars on the road each year, according to the Science article.

A team led by Genevieve Plant of the University of Michigan conducted aerial sampling over the Permian Basin and Eagle Ford Shale in Texas, as well as the Bakken Formation spanning North Dakota and Montana. Together, they account for 80 percent of U.S. flaring.

“We used a small plane equipped with highly sensitive sensors to measure the concentration methane and carbon dioxide directly downwind from flare tubes,” Plant told AFP.

“During our aerial survey, we sampled approximately 300 different flare stacks in the regions of the US with the highest number of flares.”

The fossil fuel industry and the US government operate under the assumption that flares stay lit and destroy methane, the predominant component of natural gas, with 98 percent efficiency.

But the combination of unlit flares and some flares that burned very inefficiently meant that on average the flares only destroyed 91.1 percent of the methane, according to the study.

That means methane emissions from flaring in the United States, which is among the top five countries with the highest flaring activity, is five times higher than currently officially reported.

Impact on health

After digging into the numbers, the team found that most flares actually operate at 98 percent efficiency.

But a modest number of faulty flares operate at up to 60 percent efficiency, and 3-5 percent of flares do not burn – directly releasing unburned gas into the atmosphere.

Flaring is inherently a wasteful activity natural gas related to oil production could be used for production purposes.

According to the World Bank, the amount of gas currently flared each year – about 144 billion cubic meters – could power all of sub-Saharan Africa.

Gas is burned for a variety of reasons. Sometimes this is done for safety, as the extraction process deals with high pressures that can cause an explosion.

In other cases, it may be economical when, for example, oil is the target and the associated gas is not considered worth bringing to market.

“Based on anecdotal conversations with industry experts, one potential reason flares may fail to light is high winds, and then flares remain unlit until noticed by the operator if re-ignition systems are not installed or operational.” Plant said.

The team proposed a number of solutions, the most important of which were: to reduce the total amount of flare activity, to increase it a flash efficiency as well as reducing the number of unlit flares.

Technological solutions such as re-injection of gas into oil reservoirs, which is a common practice in Alaska, may also be deployed.

“Other proposed alternatives to flaring include using the gas to power equipment on site, and storing it in compressed or liquefied form for later energy use,” Plant said.

In a related commentary, authors Riley Duren and Deborah Gordon said the findings have important health implications for the half a million people who live within five kilometers (three miles) of the three study basins.

“Unlit and partially burned flares can expose a frontline community to a cocktail of associated pollutants that pose acute and/or chronic health risks,” they said.

Methane is a powerful greenhouse gas, warming more than 80 times more than carbon dioxide in the first 20 years it enters the atmosphere, although carbon dioxide has greater strength.

Because of this, more than 120 countries have signed the Global Pledge to reduce methane emissions by 30 percent by 2030.

© 2022 AFP