Since the San Bruno explosion in 2010, Pacific Gas & Electric Co. has been upgrading its natural gas transmission system, costing US$3 billion. Through this upgrade, the company is reviewing aboveground hazards, such as buildings, trees etc. that could potentially be built on its high-pressure gas line network.
The community pipeline safety initiative programme
The programme includes investing in automatic shutoff valves to gas lines, in addition to comprehensive analysis to identify areas of safety concern. The work is meant to prevent the possibility and occurrence of underground gas leaks.
The importance of valves
PG&E stated: "Excess flow valves can immediately detect a change in pressure and restrict gas flow if a line is broken or damaged. The valves act as an added layer of protection for customers and communities by limiting the amount of gas that can escape from a damaged service line."
Excess flow or curb valves restricts the natural gas flow if the/a pipe becomes damaged. If there is an explosion or other pipe failure, the valves will improve the safety as well as “reduce methane emissions from oil and gas infrastructure and address climate change."
Have these concerns been taken into affect?
Of its own accord, PG&E applied this practice to its service territory. The 70 000 mile2, in addition to its 127 000 excess flow valves, have been installed and upgraded.
It has also upgraded its safety processes, including the withdrawal of its 847 miles of cast-iron pipe throughout the system, replaced with new seismically sound pipe. The company has also applied new gas leak detection technology.
PG&E has achieved 10 out of the 12 recommendations from the National Transportation Safety Board and have been working on the final two.
Edited from various sources Mercury News, Fierce Energy by Stephanie Roker