Journally Speaking: The eye in the sky

You are being watched, and more closely now than ever. Satellites have been observing the Earth’s atmosphere for decades, but recent indirect methane plume observations from satellite data required lots of interpretation and produced more than a little confusion. For example, a satellite-derived methane emissions map of the US using 2018 and 2019 data from the TROPOspheric Monitoring Instrument (TROPOMI) on the Copernicus Sentinel-5 Precursor satellite showed anomalous results. TROPOMI indirectly determines methane concentrations by measuring absorption from the Oxygen-A vibrational frequency band (760nm). Note that methane does not include oxygen. Although additional information was obtained from the shortwave infrared spectral range, TROPOMI claims an “error multiplication factor of 2.”

The satellite showed significant concentrations of methane in the Permian basin, where one would expect, but curiously, most of it was in New Mexico, west of the oilfields. Delaware basin showed much higher methane concentrations than Midland basin, though both have similar production activity. The cleanest area of the country incorporated the Utica-Marcellus regions, and the Niobrara-Williston basin areas were cleaner than the Midwest in general. The deviation from the highest to lowest methane concentrations, however, was only 3%. Clearly, better tech and analysis are required for this application.

This tech includes a laser tuned to a methane absorption band for direct methane measurements. Many satellites are going up with this instrument from disparate sources including the Environmental Defense Fund, Japan, National Aeronautics and Space Administration, ExxonMobil Corp., GHGSat, and the European Space Agency. Several companies have formed to process third-party satellite data for emissions.

These services will be critical in providing data to meet methane emissions regulations stemming from the Environmental Protection Agency’s (EPA) Final Rule on methane emissions, which came into effect May 7, 2024. The rule includes a waste emission charge on “super emitter” releases above 100 kg/hr. Detection of these releases can be by any means, but satellites can reveal releases that might have gone unnoticed by ground-based or aerial surveillance. Satellites can also quantify releases that may otherwise have been overestimated by calculation or qualitative observation. These data provide both accurate volumes and a verifiable start date for a release, which is crucial because in the absence of verifiable data, the start date will be assumed by the EPA, and it could extend for far longer than the actual release period.

The rule itself has come under scrutiny and resistance. The Texas Attorney General has sued to revoke the EPA’s authority to implement it. Similarly, the US Supreme Court’s recent overruling of the Chevron deference may revoke the rule and send it back to the courts or Congress for interpretation and clarification.

Methane emission reduction and fugitive emission elimination has been an accepted practice by operators since bp PLC, Shell PLC, ExxonMobil, and Chevron Corp. established the Methane Guiding Principles partnership in 2017. The partnership currently boasts 46 participating companies, most of which are major worldwide operators. The Global Methane Pledge, coauthored by the US and the European Union in 2021, included 125 countries which agreed to reduce aggregate global methane emissions by nearly a third by 2030 from 2020 levels. Even insurers are getting in on the act. Chubb insurance, for example, requires its clients to have programs for “evidence-based leak detection as a condition for underwriting.”

Worldwide methane leak detection is going to happen, and why not? It’s a valuable fuel, not to be wasted. Leak detection is expensive, however, and the EPA and Department of Energy have provided $850 million in federal funding to help implement this program. For smaller operators, subscription access to satellite data may provide the most cost-effective tool to look after their operations. There will be more than enough satellites up there looking at it, and plenty of firms ready to help them interpret the data.