An American aircraft campaign has found that Mexico’s onshore methane emissions are 10 times higher than earlier estimates, while offshore rig emissions are 10 times lower than earlier estimates. SRON scientists have been able to verify the aircraft’s onshore observations using data from the Tropomi instrument, which does not yet provide methane data over sea. The new study, published today in Environmental Research Letters, leads to a better understanding of the patterns and places where oil and gas methane emissions occur in Mexico. This is critical to taking efficient mitigation measures.
The aircraft campaign – that took place for a few days in February 2018 and was led by the Environmental Defense Fund (EDF) – measured methane emissions in Mexico’s largest oil-and-gas producing region, across the states of Veracruz, Tabasco, Chiapas, and the coast of Campeche. The scientists found remarkably large emissions from this region. As the methane emissions were estimated to be very high during these aircraft measurement days, EDF scientists wanted to verify if these emission patterns were sustained over a longer period.
verification
At the request of the EDF, SRON scientists verified the results, using methane observations from the TROPOMI instrument. “While the EDF aircraft measurements allow very accurate estimates, assigning emission estimates to separate production regions, TROPOMI enabled the verification of the total aircraft-based emission estimates from the region over a period of two years,” says SRON scientist Sudhanshu Pandey.
Gas flares
Methane is a strong greenhouse gas, roughly 84 times more potent than carbon dioxide over a 20-year period. Major sources of methane are direct venting and the inefficient combustion from gas flares in the fossil fuel industry. “When Mexican oil and gas facilities leak methane, they are wasting valuable domestic energy resources and damaging the climate,” says Daniel Zavala, EDF scientist and author of the study. “The amount of methane leaking at just one onshore facility we studied was enough gas to meet the needs of 50% of Mexico’s residential gas customers.”
ten times higher than reported
While the emissions from the on-shore processing facilities were found to be 10 times higher than the Mexican inventory reports, the aircraft surveys also showed that the offshore rig emissions were 10 times lower. This means the on-shore emissions are far higher than the off-shore emissions, contrary to what is currently stated in the inventory reports. This is critical information for the Mexican government in order to take efficient measures to reduce methane emissions from its oil and gas sector. Unlike the onshore emissions, the offshore emissions could not yet be verified with TROPOMI.The instrument does not yet provide methane data over sea. However, this will soon change as SRON is working on producing TROPOMI methane measurements over the oceans.
Publication
The new study is part of a UN-hosted research series with the Climate and Clean Air Coalition that aims to uncover and accelerate methane reduction opportunities across the global oil and gas industry. The paper A tale of two regions: Methane emissions from oil and gas production in offshore/onshore Mexico is published today in Environmental Research Letters.
Partnership
Tropomi is a partnership between Airbus Defense and Space, KNMI, SRON and TNO, commissioned by the NSO and ESA. Airbus Defense and Space is the main contractor for the construction phase. KNMI and SRON are responsible for the scientific management. TROPOMI is funded by the Ministry of Economic Affairs, the Ministry of Education, Culture and Science and also by the Ministry of Infrastructure and the Environment.