A group of volunteers from Sierra Club’s Southeastern PA Group has commissioned an exploratory mapping of gas leaks in Philadelphia. They have connected with Gas Safety USA for this mapping, the same people who mapped gas leaks in Boston a few years ago.

The gas leaks we’re concerned with are within city limits, and constitute the distribution pipeline. There are about 1,230 miles of gas pipes beneath Philadelphia.

image credit The Gas Index –thegasindex.org

Sierra Club has wanted to find the bigger gas leaks in Philly ever since a State Impact article on the subject, about 7 years ago. Why?

Gas leaks in the distribution pipes within our City could lead to, and have led to, explosions, making urban areas quite unsafe. Gas in the pipes coming into our homes is indeed methane. Methane is a potent greenhouse gas, contributing more than 80 times the warming potential of carbon dioxide over a 20-year period, says the National Resources Defense Council (NRDC) and many others. And, the fact that it’s wasted, not even used by anyone is outrageous. Many of us have planted, cared for and enjoyed trees on our own property and as street trees. Turns out that underground gas leaks are toxic to tree roots and end up killing trees; trees that have been pushing carbon back into the soil!

A mapping exercise such as this could also help to prioritize which neighborhoods should be high on the list for a networked geothermal pilot program.

A study done for Boston showed that 7% of leaks account for 50% of the lost gas. Currently, Philadelphia Gas Works (PGW) has a budget of $33 million for what they call the “Distribution System Improvement Charge” — what they’re spending each year to dig up our streets, in order to replace gas distribution lines as the public reports smelling gas. This $33 million comes from us, the ratepayers. From both a climate and a safety perspective, it only makes sense to triage — to find and fix these big leaks first, and fast.

The initial mapping of gas leak intensity has been in select areas of the city, starting with pre-selected locations and working outwards. We included Society Hill, one of the more affluent neighborhoods, as well as Point Breeze and Nicetown, some of the poorest.

image credit — https://www.picarro.com/company/press-releases/2019/picarro_and_ntt_at_deploy_natural_gas_pipeline_inspection_solution_for

Using a vehicle-mounted mass ringdown spectrometer that measures methane in the air in parts per billion, the device notes the concentration of methane (correlated to GPS location) as the vehicle is driven around a neighborhoodWhile it cannot measure absolute quantities of methane leakage, the device does a very good job of highlighting the general location and relative severity of gas leaks (higher volume leaks correspond to higher concentrations of methane in air). By driving as many streets as possible in a given neighborhood, a clear mapping of methane concentration in that neighborhood emerges, pointing out the general location of the largest leaks (super-emitters).


2015 drive thru Philadelphia

See a brief (48 second) video showing the mapping. Just as with the Boston leak mapping, we look forward to analyzing and sharing leak maps for Philadelphia.

This initial mapping is meant to demonstrate the overall scope of the gas leak problem, while leveraging the concern and influence of select social-political actors in the city.

Ideally this initial mapping will build demand and resources ($100,000 goal) for a subsequent street-by-street mapping of the entire city, which could be used to more confidently pinpoint areas of the city that have the highest leakage. The initial sponsors of this study want the results to influence PGW’s leak prioritization plans. According to a recent article, PGW thinks they have until 2050 to fix gas leaks, and can still continue business as usual of selling gas. It’s “getting to the point of criminal negligence to keep ignoring it,” said Dave Moscatello, a volunteer member of the Executive Committee of Sierra Club’s Southeastern PA Group.

This is a project in the very early stages; outcomes will be shared in a later issue.

Contact: Meenal Raval | meenal.raval@gmail.com

Sources & Additional Information:

This was written for The Sylvanian, a newsletter published by Sierra Club’s Pennsylvania chapter, and originally published here on June 26th 2021.