PG&E Working to Ensure Safety of Its Natural Gas Pipeline System

Recently, PG&E conducted a GPS survey of its entire gas transmission pipeline system and identified a number of structures, trees and other vegetation that could interfere with PG&E’s ability to maintain, inspect and safely operate its pipeline. This year, the company began a system-wide effort, Pipeline Pathways, to begin removing those identified obstacles to reduce risk over 6,750 miles of pipeline.

Safety is at the core of this project. Clearing the defined right-of-way and easement area above the pipeline of obstructions to better maintain, survey and repair the pipeline is an established best practice that helps lower the risk of external corrosion and other threats to the pipeline, including  third-party excavation pipeline damage by creating a clear visual indication of the location of the pipeline. It allows PG&E to more effectively survey and patrol the system for leaks and to respond to emergencies in a timely manner. Additionally, national pipeline safety organizations, such as the Pipelines and Informed Planning Alliance (PIPA) and the Pipeline Safety Trust, have studied and support a clear right-of-way. PIPA conducted a landmark study in 2010 that found tree roots that come in contact with a pipeline can present a high risk to the pipe’s external corrosion protection.

PG&E recently completed its own tree root study with California State University Fresno and private consultants to understand the interaction of trees with buried pipelines. Based on data collected at the excavation of 53 locations, the results confirmed the presence of trees and roots in the area above the pipeline increased the risks to the pipeline including damage to the external coating of the pipeline, which serves as the primary layer of protection against external corrosion. In addition, the study found that tree roots can wrap themselves around a pipe and cause significant stress to it, especially during events such as wind storms where trees may uproot and pull up pipes.

PG&E understands the importance of urban forests to its customer communities and has committed to mitigating the urban forest canopy losses in every city it will work in. The company is working with a team of certified arborists and biologists to help minimize impacts on vegetation, trees and wildlife habitat.  As part of the program, PG&E will provide urban forest mitigation and replant trees and landscaping in appropriate places, away from the pipeline.

PG&E is postponing the removal of trees in the East Bay Area under its Pipeline Pathways program as the company is working with cities to come to mutually agreeable solutions regarding the process for removing incompatible trees that could pose a risk to pipeline integrity and as a result, public safety. 
This program is one aspect of PG&E’s comprehensive pipeline integrity projects that includes strength testing, mainline valve automation, and pipeline replacement. For more information, visit www.pge.com/pipelinepathways.