Large scale opportunistic vehicle-based monitoring of oil and gas emissions across Alberta, Canada

Oil and gas production in Alberta, Canada is dispersed across tens of thousands of sites. Here we present opportunistic results from a major ongoing (2021 - present) methane emissions monitoring program. We used high quality atmospheric data collected with sensor packages mounted on operator trucks that regularly drive on public roads. Data were processed on an ongoing basis into site-resolved emissions rate quantifications (n = 3350), validated non-detects (n = 17076), and localizations. In Alberta, most site-level emissions measured would be unresolvable by satellites but are nevertheless targets for mitigation. We show that vehicle-based surveys from public roads can target these sites at a low cost and provide data that is necessary to monitor emissions. We further demonstrate how site-resolved data can be linked to operator, production data, and produce emissions intensity estimates on a site-by-site basis.

 

First, we detail results from 190 single-blind emissions quantification tests, detailing model bias and uncertainty modeling through various environmental conditions. We show empirical wind speed and measurement distance dependencies in detection limits and how these can be modeled.

 

Second, we examine survey data. Measurements covered a wide diversity of production styles in all seasons. Site-resolved emissions rates varied considerably among production styles and operator. Most operators’ emissions met regulatory limits. However, some emissions would exceed anticipated future regulatory standards. Repeat measurements allow for efforts to reduce emissions to be quantified. Most notably, in 2022 a large population of sites showed rate reductions of >20 g/s that may be attributable to emissions mitigation efforts by industry.

 

Emissions intensity was also calculated at the site-scale, providing a clear ranking of emissions associated with energy production that was resolvable by production style and operator. Granular intensity data highlight how certain sites strongly likely affect larger scale intensity goals.

 

Non-detect data showed that many sites are low-emitting and demonstrate that operational public-road drive-by data can quickly and inexpensively demonstrate normal, low-emissions operations, with detection limits below most satellites. Non-detect data are helpful for prioritizing mitigation efforts.

 

Overall, we demonstrate that opportunistic vehicle-based monitoring complements other scales of measurement by providing granular site- and operator-resolved emissions data with an affordable, reliable, and scalable modality.