- What is methane?
- Why is methane important?
- How does oil and gas production contribute to methane emissions?
- Why are flares a source of methane emissions?
- Why do oil and gas operators vent gas?
- What are fugitive emissions?
- How can we reduce the amount of methane emitted?
- What is being done about methane emissions?
What is methane?
Methane, the primary component of natural gas, is a potent greenhouse gas (GHG), with a global warming potential (GWP) around 28 times greater than the same mass of carbon dioxide emissions on a 100-year basis, and over 80 times more powerful on a 20-year basis. This makes methane’s contribution to climate change second only to carbon dioxide.
Why is methane important?
While methane has a significantly higher GWP than carbon dioxide, it also has a shorter atmospheric lifetime. Methane remains in the atmosphere for around 12 years. In contrast, carbon dioxide can remain in the atmosphere for over a century. As a result of both its high GWP and short atmospheric lifetime, the rapid reduction of methane emissions is one of the most important climate actions we can undertake in the short term to quickly address climate change.
Whereas gas flaring creates intense hotspots that can be easily observed on the ground and measured using satellite observations, methane is an odorless gas that is not visible to the human eye. Detecting and measuring it is particularly challenging and often requires intensive on-the-ground and airborne surveys using specialized equipment.
How does oil and gas production contribute to methane emissions?
The global energy sector accounts for approximately 40% of methane emissions from human activity, with the oil and gas industry representing over 60% of the emissions from the energy sector, according to the International Energy Agency (IEA).
Oil and gas operations release methane into the atmosphere through the wasteful practices of intentional flaring and venting, as well as through unintentional releases such as fugitive methane emissions or venting during unexpected incidents. The table below lists some of the common sources of methane emissions found in oil and gas operations as identified by the Oil & Gas Methane Partnership 2.0 (OGMP 2.0).
Methane Emissions Category | Definition | Sources |
Flaring |
|
|
Venting |
|
|
Fugitive Losses (Leaks) |
|
|
Incomplete Combustion |
|
|
*In some regulatory jurisdictions and definitions, these emissions may be called ‘fugitive emissions’ rather than venting.
In recent years the scale of methane emissions from oil and gas operations has become apparent, with advances in detection technology allowing previously undetected sources to be identified. These emissions, typically resulting from poor maintenance and malfunctioning equipment, can account for enormous amounts of methane and are often labeled “super-emitters.” While oil and gas operations are a significant source of methane globally, the industry is also ideally placed to respond quickly to and address these emissions through flaring and venting reduction, fixing leaks, and tackling super-emitters.
Why are flares a source of methane emissions?
Flaring is a direct source of methane emissions as flares do not completely combust all the hydrocarbons in the gas they burn (View our flaring explained guide). However, how much flaring contributes to methane emissions is poorly understood.
Typically, GHG estimates of gas flaring emissions are based on two core assumptions:
- that flares have a methane destruction efficiency of 98%, resulting in 2% of the methane in the flare gas stream being emitted to the atmosphere un-combusted; and
- that flares are lit and operating properly all of the time.
These assumptions, used widely, have formed the foundation of estimates of GHG emissions from flaring for decades. We estimate that in 2022 flaring resulted in 357 million tonnes of CO2 equivalent emissions (MMtCO2e), of which 319 MMtCO2e was in the form of carbon dioxide and 42 MMtCO2e was in the form of un-combusted methane.
The 98% value for flare destruction efficiency is attributed to controlled studies conducted for the United States EPA as far back as the 1980s. Flare destruction efficiency has not been widely field-tested to date because direct measurement in real-world environments is highly complex and problematic.
However, given its importance in understanding the methane emissions associated with flaring, it has become a critical area of research. In 2022, a study detailing the findings of a field campaign in the United States to measure flare destruction efficiency was published. The study found an average destruction efficiency of 95.2% for Permian, Eagle Ford, and Bakken basins facilities, considerably lower than the default 98% commonly used.
Bringing together the measured destruction efficiency of 95.2% and the prevalence of unlit flares, the researchers suggest that flares in these basins effectively operate with a destruction efficiency of 91.1%. However, the study looked at a relatively small number of flares that operate in a way that is not typical of many other locations. Nonetheless, if these findings are applicable across the US, let alone the world, the true scale of the contribution of gas flaring to methane emissions could be significantly underestimated.
The destruction efficiency of a flare is likely to be a product of many factors, including flare gas composition, flow rate, flare system design, operation and maintenance, and local environmental factors such as wind speed.
While research continues, there are three critical steps operators can take now to reduce methane emissions from flaring:
Critical actions to tackle methane emissions
- Ensure flares are always lit and have automatic systems to re-ignite if they should go out.
- Ensure flares are operating effectively and optimize flare destruction efficiency.
- Reduce and ultimately eliminate the gas going to the flare, which should always be the end goal.
GGFR has developed an interactive dashboard to help demonstrate the likely GHG emissions from flaring across various circumstances.