Motorists traveling on I-95 through Liberty County this week probably have noticed a helicopter hovering low over the salt marsh near the northbound lanes. Eighty- to 100-foot steel poles necessary to support high-voltage power lines are being installed with an air-crane helicopter, according to Jeannine Haynes, public affairs director for Georgia Transmission Corporation.
Haynes said Coastal Electric Cooperative identified the need for a second high-voltage electric-transmission line to connect the Burnt Church Substation in Bryan County with the Tradeport East Industrial Park Substation in Liberty County. She said Georgia Transmission is installing the power line with a helicopter and special equipment like a Hydratek, a multi-purpose, amphibious vehicle.
This equipment allows the power-line project to run through the salt marshes with as little damage as possible to the environment, she said.
“There is one thing you can’t be sure about,” Haynes said. “Of course, we test the soil to determine how wet it is, but you never can be sure until the poles are vibrated in place. We’ve had no problem installing these poles, though.”
She explained that by law the poles cannot be dug into the salt marsh, which is a protected area. The poles have to be vibrated into the ground with a gigantic hammer that sits atop the foundation pole, driving it slowly into the ground. The foundation pole, a 20,000-pound platform called the power-plant box, and the vibrating hammer each are set in place by the air crane.
When the foundation pole has been hammered to the proper depth, Haynes said the helicopter delivers the rest of the steel pole.
Haynes paused to watch the pilot hover over a foundation pole, slowly lowering the main pole shaft. In short order, the pilot capped the foundation pole with the main pole shaft.
She said concrete poles also are used, but they’re installed into solid ground. Even though the steel poles are installed in a wetlands area, she said they have a lifespan of about 90 years.
Project manager Herb Payne said the helicopter will be used to thread the power lines from pole to pole after all 102 steel and concrete poles are in the ground,
He said the air crane has three 450-gallon fuel tanks. The amount of fuel used each day depends on how long the aircraft is airborne and how much weight it has been carrying.
“They started working on this line Saturday,” Haynes said. “They average (installing) four or five poles a day. Originally, we were supposed to begin construction in April, but our steel order was delayed. Our project completion date is still October, though.”
Haynes explained that the pilot will “leap frog” components from one pole up the line to the one above it, piece by piece. When the vibration hammer and power-plant box have been moved the 500-foot span between the poles, the line crew climbs into the Hydratek to move to the next pole.
“(The Hydratek) does not muck up the soil, and it doesn’t kill the plants,” she said. “Part of our goal is to minimize the impact on the environment.”
She said other measures used to minimize effects on the environment include having two-thirds of the project parallel I-95 and Islands Highway and cutting trees at ground level. The 12.2-mile long power line will include 6.5 miles in Bryan County and 5.7 miles in Liberty. She added that the projected cost for the new power line is $20 million.
According to GTA’s website, in 1974 Georgia’s customer-owned electric cooperatives pooled their resources to create a statewide power generation and electric transmission co-op. Georgia Transmission was formed in 1997 when Oglethorpe Power was divided into three companies. Like Georgia’s EMCs, GTA is a nonprofit cooperative.
The website said GTA plans, builds and maintains high-voltage power lines and substations for 39 of Georgia’s 42 customer-owned electric membership cooperatives. The GTA builds more than 50 power lines and 15 substations each year.