🚨New Paper Alert🚨In a first study of this kind, we *empirically* show that leak detection and repair programs - a common methane policy tool - are indeed effective at reducing emissions over many years of implementation. We also found a few surprises. 1/ iopscience.iop.org/article/10.108… 
First, emissions reduced by 44% between two LDAR surveys conducted over a period of 0.5 - 2 years from the initial survey.
Compare this to EPA (or other state policy) assumptions that annual surveys reduce leaks by 40%. Pretty close. But, note I said emissions, not leaks. 2/
Compare this to EPA (or other state policy) assumptions that annual surveys reduce leaks by 40%. Pretty close. But, note I said emissions, not leaks. 2/
Important context:
Methane emissions consists of leaks (unintentional, fixable) and vents (intentional, not fixable). Leak detection policies only target leaks.
But, some vents can be fixed because they vent far more than what they were designed for. These anomalous vents. 3/
Methane emissions consists of leaks (unintentional, fixable) and vents (intentional, not fixable). Leak detection policies only target leaks.
But, some vents can be fixed because they vent far more than what they were designed for. These anomalous vents. 3/
What LDAR policies do is that they force companies to fix these anomalous vents (esp. on tanks). This is critical because vents are a far bigger problem than leaks.
So, 44% ⬇️ in emissions is really 22% ⬇️ in leaks and 47% ⬇️ in vents.
Policy analysis miss this. 4/
So, 44% ⬇️ in emissions is really 22% ⬇️ in leaks and 47% ⬇️ in vents.
Policy analysis miss this. 4/
So, LDAR policies not only help reduce leaks, they also help reduce anomalous vents.
We also find that repair is highly effective: >90% of leaks fixed do not come back. But, *new* leaks are generated.
This is an important result for state and federal methane policy. 5/
We also find that repair is highly effective: >90% of leaks fixed do not come back. But, *new* leaks are generated.
This is an important result for state and federal methane policy. 5/
Finally, low-production sites emit an order of magnitude more methane on a proportional basis than high-production sites.
Industry has argued for exemptions for low-producing wells because of low methane emissions. Our data clearly shows that's not true. /End
Industry has argued for exemptions for low-producing wells because of low methane emissions. Our data clearly shows that's not true. /End
Also, shout out to brilliant colleagues and co-authors across two countries: @StanfordEarth, @UBC, and @UCalgary! Collaborations across international borders can be challenging, but this project was really fun!
@StanfordEarth @UBC @UCalgary For those who are interested in the primary data, here's a link to the data repository. This is my first time using the dataverse and I really like the option of having a DOI just for the datasets. dataverse.harvard.edu/dataset.xhtml?…
