A team led by the University of Michigan discovered that the nation's largest offshore fossil fuel production basin has twice the climate warming impact as official estimates by directly measuring greenhouse gas emissions from an airplane flying over the Gulf of Mexico.
The findings could have an impact on future energy production in the Gulf, as decisions about expanding oil and gas extraction are based on climate impact calculations.
While there has previously been a gap between reported and measured methane emissions in the basin, this study is believed to be the first to quantify methane and carbon dioxide emissions and identify the main culprits.
It turns out that older, closer-to-land platforms emit far more methane than is reported in government inventories.
Gulf Offshore Oil And Gas Production Has Double The Climate Impact
Sean Rayford/Getty Images
The researchers conducted their atmospheric measurements by flying upward and downward in a cylinder pattern around the platforms, measuring the amounts of carbon dioxide and methane released, as per Phys.org.
They combined aircraft measurements with all previous field surveys to collect the largest sample size of GHG emissions from Gulf of Mexico platforms.
Their observations quickly drew attention to specific oil and gas production operations.
According to Eric Kort, U-M associate professor of climate and space sciences and engineering, principal investigator of the F3UEL project, and corresponding author of the study published in the Proceedings of the National Academy of Sciences, they discovered a certain type of shallow water platform had large methane emissions that elevated total greenhouse gas emissions for the entire Gulf of Mexico.
These are larger "central-hub" multiplatform complexes that collect and process oil and gas from small production platforms.
Due to direct venting into the atmosphere or releases from tanks and other equipment, sampling revealed that these emit more methane than expected.
Actions to reduce these large methane emissions, whether by capturing the gas, flaring it instead of venting, or repairing or abandoning facilities, could have a significant impact on the climate.
The discovery is similar to one made by the same team in September, which discovered that inefficient flaring operations on land were releasing five times more methane into the atmosphere than expected.
These studies, taken together, highlight the need for a more comprehensive method of assessing greenhouse gas emissions, and thus the climate impact of oil and gas production in a given region.
The "carbon intensity," a metric for the levels of greenhouse gases emitted per unit of oil or gas produced, determines climate impact.
When new oil and gas projects are being considered, regulators consider whether the carbon intensity of the new projects will be the same or lower than the carbon intensity of expanded production elsewhere.
This has already had an impact on decisions regarding the sale of oil and gas leases in the Gulf of Mexico.
However, estimates of carbon dioxide and methane released into the atmosphere in these assessments have historically not been based on direct measurements, and many of them have not included methane emissions.
The study's first author, Alan Gorchov Negron, a U-M graduate student research assistant, has presented the climate impact of both oil and gas production as an observation-based carbon intensity.
This metric captures real-time climate impacts and provides an easy way to integrate the growing number of field surveys of emission levels from the manufacture of fossil fuels into a consistent metric.
Natural Gas Exploration, Drilling, And Production Affects The Environment
When geologists explore natural gas deposits on land, their vehicles may disturb vegetation and soil.
Drilling a natural gas well on land may necessitate clearing and leveling the surrounding area, as per EIA.
Well-drilling activities pollute the air and may endanger people, wildlife, and water resources.
Pipelines that transport natural gas from wells typically necessitate the clearing of land to bury the pipe.
Natural gas production can result in large amounts of contaminated water.
This water must be handled, stored, and treated properly so that it does not pollute the land or other bodies of water.
Engines used to power equipment and compressors in natural gas wells and pipelines produce air pollutants and noise.
Natural gas is burned (flared) at well sites in areas where it is produced at oil wells but is not economically transportable for sale or contains high concentrations of hydrogen sulfide (a toxic gas).
Depending on the chemical composition of the natural gas and how well it burns in the flare, natural gas flaring emits CO2, carbon monoxide, sulfur dioxide, nitrogen oxides, and a variety of other compounds.
Flaring, on the other hand, is less dangerous than releasing natural gas into the atmosphere and results in lower overall greenhouse gas emissions because CO2 is not as powerful a greenhouse gas as methane.
