Wednesday, September 15, 2010

Enstar Says Catastrophic San Bruno-Type Natural Gas Explosion Less Likely In South Central Alaska Than In The Lower 48

The catastrophic explosion of a primary natural gas distribution line and resultant fire in San Bruno, California, has national implications. A subsequent Yahoo News story revealed that more than 60 percent of the nation's gas transmission lines are 40 years old or older, and that the U.S. has more than 2 million miles of pipelines.

Yet despite these broad implications, only one local Alaska media outlet had the presence of mind to contact Enstar, the primary natural gas distributor in South Central Alaska, and ask them if we were also vulnerable. According to KTVA Channel 11, Enstar's response was that we are not as vulnerable in Alaska as the Lower 48. The primary reasons:

-- Newer system and more contemporary equipment. Enstar started up in 1961. The oldest pipes are just approaching 50 years old now. The majority of their pipes are of higher-quality steel. They believe current lines could last up to 100 years, with proper recurring maintenance.
-- Less pressure and dryer gas. The distribution lines are run under significantly lower pressure than in the Lower 48. In addition, the source gas is a dryer gas. This reduces the rate of internal corrosion.
-- Vigorous inspections. In response to a federal law called the Integrity Management Program, which requires all natural gas utilities to inspect their pipelines by 2012, Enstar has already inspected 90 percent of their pipelines, and plans to be finished next year, ahead of schedule. It would have been useful for Enstar to have been more proactive and issue a press release to inform Alaskans of the status of their lines; that's why they have a public relations department, I presume.

But the Los Angeles Times has published a story about another issue -- shutoff of natural gas once a distribution line has exploded and triggered a fire. At a San Bruno town meeting on Monday September 13th, Pacific Gas & Electric revealed that it took about an hour and 46 minutes to stop the gas. They blamed part of the delay on the fire, saying that it was unsafe for workers to approach the valves. In response, the National Transportation Safety Board representative said the valves were, respectively, a mile and a mile-and-a-half on either side of the blast site, but did not elaborate on how the fire might have interfered with shutting off the gas. One state lawmaker intends to introduce legislation in Sacramento later this year to require either remotely activated valves or automatic shutdown devices in large natural gas pipelines, claiming that such safety systems could have stopped the gas flow in five minutes and would have prevented a tremendous amount of damage. The majority of the destroyed homes were lost as a result of the prolonged wind-whipped fire rather than the initial explosion.

Federal and state governments do not require operators to install automatic shutoff valves, leaving it up to the discretion of the company that owns the pipeline. But the issue has been hotly debated for years; objections are based upon the projected increased costs as well as the possibility of shutdowns triggered by false alarms. We all know how frequently car alarms go off for no apparent reason. However, while it's probably impossible to design a system which will shut down a major gas pipeline in five minutes without risking the inconvenience of too many false alarms, a 1 hour 46 minute response time is absolutely unacceptable.

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