A gas line upgrade program across upstate New York is targeting the Schenectady area this month, as National Grid retires aging iron pipes beneath the streets of Schenectady, Scotia and Glenville.
And with the new materials used in the replacement pipes come new techniques for installing them — precision drilling requiring a few neat holes instead of wholesale trenching.
The latest portion of the project, which will total 98 miles in 2017 and 2018, is a 2,400-foot stretch of gas main along Engleman Avenue, serving houses on the Scotia/Glenville border.
The current cast iron pipe dates to the 1930s, and while it hasn’t been leaking, it is of the age and design that is prone to leakage. Crews are now finishing their work to install pliable plastic lines that will take over the function now handled by the cast iron pipes. The final cost will be in the $350,000 range, which is less than the average $1 million per mile such work usually costs.
The costs are a big part of the 24.8 percent rate hike National Grid is seeking for its upstate customers starting April 1, 2018.
At 50 miles a year, it will take about 15 years for the initiative to reach all of National Grid’s upstate service area, where it has 600,000 customers.
National Grid spokesman Patrick Stella said the switch from iron to plastic is mandated by the state Department of Public Service but also necessitated by circumstance: aging cast iron pipes are more likely to leak.
“Cast iron’s held up for a long time,” he said. “Just because it is cast iron doesn’t mean it’s leaking [but] we’re trying to be proactive because a lot of our cast iron pipe has been in for decades.”
How fast the work progresses will depend in part on how much of a rate hike National Grid is granted. Its request is currently in the hands of state regulators and will be the subject of months of hearings and investigation, with active pushback from consumer advocates and other opponents. If the Public Service Commission rejects the nearly 25 percent rate hike in favor of a significantly smaller rate hike, it might also allow for a longer phase-out period for cast iron pipe.
(The price of the gas flowing through the pipe is separate from delivery charges; the utility does not set that price or derive any profit from the gas itself, and the state does not regulate the price.)
This summer, National Grid is installing 2.11 miles of plastic pipe beneath the streets of Scotia and Glenville and 6.14 miles beneath the streets of Schenectady.
In Scotia on Monday, a crew was moving the Engleman Avenue project along to completion. Supervisor Pat White said the modern techniques leave the old cast iron pipe in the ground — it is said to be “retired,” rather than “replaced” — but also leave much less scarring on streets and lawns and result in a lower price tag.
It is, essentially, a process akin to laparoscopic surgery, with the work begin done out of sight beneath the surface with fewer and smaller incisions.
Cast iron gas pipes like these that were removed from the ground are being taken out of service across upstate New York by National Grid. (Provided)
The horizontal drilling rig bores into the ground, levels out and sends a boring bit as much as 500 feet down the block, staying about 2 feet below the surface. As the operator runs the machine, a second worker uses a locator and walks along above the boring head as it advances.
“That locator actually talks to the machine, so it will tell the machine exactly how deep they are as they’re going along,” White said. “That bore head has a transmitter in it, that tells it exactly how deep it is, what angle it’s at, so they’ll go along and talk to each other, keep it on the right path.”
At the end of the run, the operator turns the head of the mechanical worm up, and it digs itself out into sunlight again. The crew attaches a reamer head that’s 1.5 times the diameter of the pipe that will be installed, then pulls it back underground to the starting point. Along the way, it extrudes a slurry of sodium bentonite that hardens the little tunnel and makes it easier to get the plastic pipe in, without any cave-ins. That done, the drill is pushed all the way back through. The new pipe is connected to it and pulled back through to the starting point.
Laying a 500-foot pipe in this manner is better in all respects than digging out and refilling a 500-foot trench.
“This is the way everybody’s going these days,” White said. “It’s a huge cost savings in terms of restoration.”
A hole must still be dug in front of each house, to allow for hookup to the new plastic gas line out near the street. But here again, technology is making the work quick and neat.
A series of precisely dug holes lines the lawns on Engleman, their corners square and their walls straight like a box. They were bored out with a hydrovac, which injects water into the ground and vacuums out the resulting mud.
“That cuts way down on our restoration costs,” White said. “Normally we’d have to dig all these holes with a backhoe. It literally takes five minutes — you stick a hose in the ground and it sucks the dirt out.”
The minimum depth for the new pipe is 24 inches, so the National Grid crew aims for 32 inches, to allow a buffer for small dips and bumps. The line may or may not wind up below the frost line — it doesn’t matter, because the new pipe is flexible enough that frost won’t damage it.
Stella said along with the scheduled program of pipe installation, stretches of cast iron pipe found to be leaking will be retired on an emergency basis.
Replacement of leak-prone pipes and public education on gas safety has become a priority initiative for the PSC.
The PSC in April 2016 announced an accelerated effort to take leak-prone gas pipes out of service, and announced increased financial penalties for utilities that missed their targets. It also ordered utilities to increase their public education efforts about gas safety.
The PSC earlier this month issued a report on gas safety performance measures, finding considerable progress by the state’s utilities in reducing the year-end backlog of known, potentially hazardous leaks. The total in 2016 was 58 statewide, down from 68 in 2016 and 1,154 in 2003.
As the number of leaks was decreasing, the number of reports by the public of potential gas odor increased, possibly due to increased public awareness of gas dangers, the June 15 report indicated.
In its upstate operations, National Grid showed a decrease in all known gas leaks from 2015 to 2016 but an increase in known potentially hazardous leaks.