The Washington Utilities Transportation Commission (WUTC) on Friday approved long-term, multi-year plans costing nearly $700 million for the state’s four investor-owned natural gas utilities to upgrade their respective pipeline systems in lieu of stiffer federal regulations since a series of pipeline ruptures and explosions in the West and elsewhere around North America in recent years.

Unlike similar plans in California that involve extensive high-pressure transmission pipeline systems (see Daily GPI, Dec. 24, 2012), the utility plans in Washington state are focused almost exclusively on smaller-diameter, lower-pressure distribution pipelines.

In 2011, the federal government adopted a program that requires gas distributors to develop procedures to ensure the safety and reliability of their delivery pipelines. “The new regulations require operators to identify the conditions, characteristics or threats that cause leaks in order to make their systems more reliable and safe,” WUTC said.

WUTC last year directed each of the companies to survey its pipelines and propose plans for replacing lines having “elevated risk.” As an incentive, regulators allowed the utilities to recover their costs each year during the multi-year programs, rather than waiting for formal rate case proceedings.

WUTC Chairman Dave Danner said the utility plans show a “commitment to safety” by each of them, even though Washington has very little “more dangerous” cast iron pipelines, which have failed in other parts of the country where the natural gas infrastructure is much older.

“The utilities all have sound plans going forward to replace some plastic pipe that has shown a tendency toward minor cracking,” Danner said.

The four gas utilities have each identified pipe targeted for replacement and described how they assessed risk and established replacement priorities and schedules for determining the location of elevated-risk pipe, WUTC said.

Spokane, WA-based Avista has about 3,400 miles of pipeline in Washington, and over the next two years it plans to replace about 60 miles of pipe in unincorporated Spokane County. Bellevue, WA-based PSE has more than 12,000 miles of pipeline in the state and plans to upgrade 400 miles of plastic pipe during the next 20 years. In the next two years, PSE will upgrade 60 miles of that pipe in scattered areas around its territory in northwest Washington.

Kennewick, WA-based Cascade has almost 4,500 miles of gas pipelines in the state, and it plans to replace 62 miles of bare steel pipe by 2015 in three areas: Longview, Shelton and Anacortes. Similarly, Portland, OR-based NW Natural has 1,700 miles of pipelines in the state, and it is scheduled to replace all of its bare steel pipe by the end of next year.

The utilities plan to spend nearly $700 million collectively with PSE spending the bulk of the money ($670 million over 30 years), the WUTC spokesperson said. For the others, Avista plans to spend about $10 million over the next 20 years; Cascade plans to spend $12.3 million in its first year; and NW Natural plans to spend $6 million spread over the next four years.