The Public Service Commission of the District of Columbia (PSC) has given Washington Gas Light Co., a subsidiary of WGL Holdings Inc., conditional approval to implement the first five years of a 40-year plan to replace aging, corroded or leaking natural gas pipelines under the nation’s capital.

According to documents filed with the PSC, Washington Gas’ revised plan — also known as the Accelerated Pipe Replacement Plan (APRP) — will cost an estimated $1 billion over the full 40-year term. But the utility has only requested to implement the first five years of APRP, which is expected to cost $110 million.

During the first five years of APRP, Washington Gas plans to spend $40 million to replace an undetermined number of bare and/or unprotected service replacements; $32.5 million to replace 18 miles of bare and unprotected steel main and an undetermined number of services; and $37.5 million to replace 20 miles of cast iron mains.

“[Washington Gas] anticipates that the annual spend for each of the programs will vary year to year based on fluctuating risk profiles, changing operational conditions and/or construction efficiency opportunities,” PSC said. “However, these spending targets are expected to provide strategic direction for allocating plan resources on a long-term basis. Year-to-year selections will be developed based on both the short- and long-term considerations.”

Documents filed with PSC also showed the cost to replace bare and/or unprotected steel pipes, as well as 23,600 service lines, over the next 15 years is estimated at $118 million. Another $97 million would be needed over the next 15 years to replace 54 miles of steel main and 4,562 service lines. The replacement of all cast iron pipelines in the district — including 66 miles of large-diameter cast iron pipelines, 428 miles of main and 8,625 service lines — is estimated to cost $800 million.

PSC granted approval to APRP, on the condition that Washington Gas provides within 30 days a list of its projects and their individual cost estimates, and descriptions of the systems and personnel the utility will use to coordinate the projects and to identify and procure contractors to do the work.

“We are pleased that the PSC is working collaboratively with us on improving the District’s aging gas pipeline infrastructure at a faster rate,” said WGL CEO Terry McCallister. “This will allow us to continue to provide our customers with safe and reliable natural gas service for decades to come.”

PSC has not approved the funding mechanism for APRP. “We will hold an expedited evidentiary hearing to allow parties the opportunity to raise questions on the revisions that we have directed [Washington Gas] to file as conditions of our approval today, and on the clarifications that we have outlines are needed for the funding mechanism,” the agency said.

Comments from other parties regarding Washington Gas’ plans are due within 60 days of the order [No. 17431].