Methane (CH4) is a powerful greenhouse gas (GHG), whose global warming potential is 80 times greater than CO2 over a 20-year period. Methane is responsible for at least 25% of global warming attributable to human action. Therefore, it is obvious that reducing methane emissions – in addition, of course, to CO2 emissions – is a climate policy imperative. There are several sources of methane emissions. Cattle ranching (27%), rice production (7%), the anaerobic decomposition of organic waste in dumps and sanitary landfills (11%), coal mining (9%), and of course, the oil and gas industry (24%). It must be remembered that natural gas is essentially methane. In this context, various countries, including Mexico, have formulated and signed commitments to reduce methane emissions, part of which are integrated into the Paris Agreement through the Nationally Determined Contributions (NDC, for its acronym in English).
Mexico is the 12th largest producer of oil in the world, with 1.6 million barrels per day, and a gas production of 4,900 million cubic feet per day. 80% of the oil and 60% of the gas are produced in shallow marine fields (offshore). It should be noted that almost all of the gas produced in Mexico is gas associated with oil extraction, and that around 11% of the total is burned or vented into the atmosphere due to lack of infrastructure to collect and convey it. This is equivalent to approximately half of the domestic consumption of natural gas in our country. It should be noted that the information available in Mexico on the corresponding emissions of methane and CO2 into the atmosphere is highly variable and uncertain, and that the official emission inventories are contradictory.
In 2018, the Mexican government (ASEA) published a set of regulations to reduce emissions associated with the oil and gas value chain, which was the basis for commitments to reduce methane emissions before the Paris Agreement (Contribution NDC), as well as the trilateral agreement with Canada and the United States for methane emissions linked to the oil and gas industry. However, this was not accomplished, and given the uncertainty in our country’s emissions inventories, it is currently not possible to adequately identify the sources and the necessary reductions, nor to monitor, evaluate, and follow up on commitments and agreements.
However, based on PEMEX’s own data reflected in the Annual Operation Certificates of different facilities in the sea, it is estimated that 70% of methane emissions derive from the inefficient and incomplete burning of natural gas, and 30% of its simple venting to the atmosphere. It is obvious that, in order to reduce methane emissions, the gas must be collected in its entirety, transported in pipelines, combustion efficiency significantly improved when burned in the atmosphere, and pipelines, valves and compression installations repaired and sealed to minimize leaks. . This has been attempted since 2008, when actions were taken to capture and channel marine gas to compression and processing facilities on land, basically to Atasta (Campeche), Ciudad PEMEX and Nuevo PEMEX in Tabasco. Recent studies¹ suggest that while marine emissions have decreased, emissions on land have increased substantially. That is, simply, the burning and venting of gas (methane) in the sea was transferred to facilities on land. In fact, emissions on land are estimated to be two orders of magnitude higher than what inventories report. Therefore, it is very likely that the total methane emissions in the oil and gas sector in our country are much higher than those reported by official sources. The burning and venting of gas on land is, on the other hand, a huge source of contamination by volatile organic compounds and polycyclic aromatic hydrocarbons (which are carcinogenic), sulfur oxides, nitrogen oxides and inhalable particles. Clearly, they represent a serious public health problem in Ciudad del Carmen and Villahermosa.
For these reasons, and as presented to the Forum of Major Economies on Energy and Climate last week, President López’s offer to reduce methane emissions by 98% is a lie. Under current conditions, without credible inventories, and without objective information derived from in situ, aerial and satellite measurements, it is impossible.
¹Daniel Zavala-Araiza et al. 2021. “A tale of two regions: methane emissions from oil and gas production in offshore/onshore Mexico”. Environment. Res. Lett. 16 024019
Civil Engineer and Economist
Mexican politician, liberal environmentalist and researcher, he has served as a public official and activist in the private sector. He was the candidate of the Nueva Alianza party for President of Mexico in the 2012 elections.