August 2011, Vol. 238 No. 8
Features
First Tier 4 Machines Tested On Tennessee Valley Gas Line Construction
The Tennessee Valley Authority serves 9 million customers in seven states, and two-thirds of its power is generated from coal. So the fact that Spectra Energy is installing a 24-inch gas pipeline through northern Tennessee to feed a TVA power plant is news in itself. But the construction of the North East Tennessee pipeline (NET), due to be completed in September, touches on some of the most discussed issues in the industry.
Emissions Standards Drive Development
Tightening emissions standards are at the core of the project. Barbara Martocci of TVA explains, “We have a vision to be a reliable, clean provider of energy. We have worked to continue providing electricity to the 9 million consumers in the valley, and one of the things we are doing is reducing our dependence on coal while we continue to provide that power.” TVA has one gas plant in middle Tennessee already completed, with a second under construction, and according to Martocci, there’s no question that right now TVA’s usage of natural gas for power generation is increasing, even if the question of fuel sources for future plants remains up in the air.
Rising standards make a strong argument for natural gas. “As we look at our coal plants, the cost to add emissions controls and to meet the regulations that are continuing to come down from the Environmental Protection Agency, we also have to look at all of the other costs associated with operating a plant and make those determinations, what’s the best generation mix for the valley residents.
“That gas that we are going to be using burns more cleanly than coal, so we are able to reduce our emissions.”
The NET also has the privilege of brand-new equipment technology engineered to meet higher emissions standards : eight Caterpillar excavators, six of the 349E model built in Aurora, IL, and two 336Es from the factory in Japan. “The 349Es are the first six that will be delivered anywhere through Caterpillar,” says Mike Dearing, account manager for PipeLine Machinery International, the pipeline specialist Caterpillar dealer. “For the 336Es, U.S. Pipeline is the first North American contractor to get them. We’re going to ship at least six of them out here to Tennessee.”
In addition to several design and comfort upgrades, the excavators align with EPA Tier 4 standards limiting NOx and particulate emissions and requiring decreases of 90% from previous levels by 2014. Filtering and engine design strategies are in development industrywide to determine the best ways to reach these standards. “Caterpillar’s new machines have a diesel particulate filter that takes the soot and burns it to ash when it reaches a certain point in the machine, leaving cleaner air going out into the environment,” Dearing explains.
Asked about the new excavators at the outset of the project, U.S. Pipelines’ project superintendent Dana Bratcher was enthusiastic. “For the pipeline business, the challenge is trying to keep up with equipment technology. These machines have far superior digging power and hydraulics. And I’m excited to see the computerized cameras they’ve got on them. When we can improve safety and performance at the same time, that’s a great thing.”
Of course, new technology isn’t always a smooth ride, and in Tennessee, those shiny yellow excavators were in for a tough maiden voyage.
Difficult Landscape, Busy Neighborhood
The project’s specific tasks involve 30 miles of loop work around an area about 80 miles square, taking up old natural gas lines 12 or 8 inches in diameter and replacing them with 24-inch pipe. The terrain is rolling, with steep-sloped hills and valleys dominating the view.
To Bratcher, the primary challenges are obvious: “The hills. Mountains, to me, are a mile up there. These are just short hills, but there are adverse conditions. The weather has not been very cooperative at all.” Weeks of unseasonable rain on the steep hillsides made for treacherous footing from project kickoff in May throughout the beginning of June. The project was limited to a narrow right-of-way, in part due to existing infrastructure. And the ground itself was mostly rock.
Public relations, too, are an area of interest, just as they have been in many recent pipeline projects. “Some of this area is rural, some of it is pretty populated, so it’s difficult to maneuver through these areas with our trucks. It’s congested,” says Bratcher. “From a public standpoint, they’re not used to construction in this area, so we’re impacting their lives too. It’s good for the community, good for the city, good for growth, good to stimulate the economy here, but no one likes to see change.“
The pipeline owner, Spectra Energy, took a proactive stance on community outreach. “Response and interaction with the local communities has been positive, and we continue to foster those key relationships. East Tennessee Natural Gas has existing pipeline infrastructure throughout northeastern Tennessee, and thereby is able to utilize existing utility corridors and minimize stakeholder and environmental impact,” said Andrea Grover, director of Spectra Energy’s stakeholder outreach. “We remain committed to maintaining an open line of communication with all of our stakeholders throughout the entire NET Project process.”
Bratcher affirms the focus. “They’ve had town hall meetings to let everyone know what’s going on, let everyone get involved for those who want to be active in it. This is a pipeline corridor that’s existed, so that’s nothing new to them. It’s just a little bit of growth.” Still, he says, “We’re trying to make as small a footprint as we can through this country.”
Hard-Won Progress
By mid-July, the project had shaken free of early weather delays and was in full swing, although the challenge of the terrain fulfilled its promise. “Seventy-five to 80% of it’s been rock. We’ve shot a lot of rock and we’ve machined a lot of rock and we’ve dug a lot of rock. We’ve had a lot of two-toned areas, a lot of tight restricted areas because of an existing hot line that we’re parallelling, that’s been another challenge,” Bratcher reported. However, clearer weather throughout June and July and an increase in number of workers kept the schedule on track, and a September 1 completion date looked likely as of this article’s press date.
As for the new excavators, they’ve earned praise under the tricky conditions. “I talked with my ditch crew the other day and they’ve had great success with them. They’re holding up to the actual changing of the soil conditions. That’s some pretty tough rock up in here in northeast Tennessee, and they’ve managed that. They’ve walked through these hills and handled the inclines well. They just seem to have more power than the older machines. “
Closer to Bratcher’s heart is the commitment the investment in new equipment represents to the workers. “We’ve had some great people come up and work in these hills. As a construction worker, it’s a great thing to see companies keep up with the technology, whether it’s an excavator or a dozer or whatever, and put money back in the business to make the folks out in the field safe.”
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