|
Power plant began generating 65 years ago this week
By Lynn Hotaling
Also see then and now
One of Jackson County’s more fascinating tales is the history of a local engineering marvel – a network of tunnels and steel pipe that channels the Tuckaseigee River’s West Fork through the mountains to a powerhouse below – completed in just 16 months and dedicated exactly 65 years ago.
With World War II already raging in Europe, crews in Jackson County worked around the clock to build a massive hydroelectric project aimed at providing power for an aluminum plant in Tennessee.
When the Aluminum Company of America began construction of the Glenville (now Thorpe) dam, lake and powerhouse, it did so in order to step up the output at its plant in Alcoa, Tenn. – capacity that was needed to produce airplanes for the Allied war effort.
Sixty-five years ago, local dignitaries joined the governor and officials from Nantahala Power and Light Co. and its parent company, Alcoa, for the dedication of the Glenville hydroelectric project, which produced its first electric current that day – Oct. 13, 1941. The ceremony took place just upstream of the power plant, which is located on N.C. 107 beside the Tuckaseigee River’s West Fork. Water to power the turbines flows through a system of tunnels and pipeline to reach the generating plant, which is almost 1,200 vertical feet below, giving the plant the highest head (vertical drop) of any hydroelectric turbine east of the Rockies. – Photo courtesy Fred Alexander/Duke Energy
“When Thorpe came on line, we were producing enough power to make aluminum for two B-25 bombers per day,” said the late Charlie Stewart, who was Thorpe’s superintendent for some 35 years.
The story of that big steel pipe supported by tall towers that can be seen from N.C. 107 while traveling to and from Glenville is nothing short of amazing.
Impounded by a 150-foot-high dam, water from the 4.5-mile-long lake travels through 3 miles of tunnels and steel pipe and drops a total of 1,207 feet before reaching the powerhouse in Tuckasegee. This gives Thorpe the highest head (vertical drop) of any power plant east of the Rocky Mountains and allows the plant to produce more energy with less water.
The three 9-foot-diameter tunnels total 4,803 linear feet and were drilled through solid rock with crews working from each end of each tunnel.
“That meant the job went three times faster than if they’d drilled one long tunnel,” Stewart told The Herald in a 1990 interview. While drilling proceeded on the tunnels, other crews built the dam and powerhouse, he said.
Engineers checked the tunnels daily to make sure crews working from each portal stayed on course.
“They’d run lines up over the mountains and down and follow the drillers through to keep them on line,” Stewart said. “When the tunnels were drilled through, they were always right on target, give or take a few inches. It was a big event when the two ends would meet.”
Construction began in June 1940, and despite the county’s greatest natural disaster – the August 1940 flood – the plant began producing electricity on Oct. 13, 1941. It took 1,500 men to complete the project that fast, Stewart said.
While the plant was under construction, it was feared that German agents would try to sabotage the project that aimed to provide a boost to the war effort. Army troops patrolled the area, and guards were placed at the tunnel entrances, Stewart said.
“They never actually caught anyone around here, but they did catch some German saboteurs in a small submarine off the North Carolina coast,” he said. “It was thought at the time that their target might have been Alcoa – either the aluminum plant or the power plants.”
Now owned by Duke Energy, the Thorpe project (then known as Glenville, the project was renamed in 1951 in honor of J.E.S. Thorpe, Nantahala Power & Light’s first president; the Glenville name was restored to the dam and lake a decade or so ago, but the powerhouse remains the Thorpe Plant) was constructed by Nantahala Power and Light Co., which was a subsidiary of Alcoa. Duke bought NP&L in 1988, but it remained a separate company until 2001, when NP&L became Duke Power-Nantahala Area. The corporate name changed again earlier this year, and the power company is now Duke Energy.
According to a 1991 report by longtime NP&L Vice President Ed Tucker, the Glenville project was on the cutting edge of technology at the time of its construction. Its earth-and-rock dam was a new type that was used for the first time in the Glenville and Nantahala (NP&L’s largest dam, Nantahala is in Macon County) dams. Both incorporate what was a new feature at the time – earthen fuse plugs built into the dams at the spillway entrances. In the event of extraordinarily high floods, the fuse plugs would give way to protect the dam and property downstream, according to Tucker.
Thorpe’s turbine is a horizontal unit with a turbine on either side of the generator. Water, which takes three hours to travel from the dam to the turbines, enters a progressively narrower channel that splits “like a wishbone” at the power-house. By the time the water reaches the twin turbines, it has been “squeezed” into two 10-inch streams; as the jets of water hit the turbines, they produce 6,300 pounds of thrust every 4.5 seconds, Tucker wrote.
Thorpe is one of six hydroelectric plants Duke owns in Jackson County and is by far the biggest of those, though it’s the second-largest in Duke’s Nantahala Area.
It was 65 years ago this week that 500 people gathered by the power plant to mark its completion on a day of “sunshine and autumn colors,” according to one newspaper report.
After what was described as “a stirring, patriotic speech,” then- Gov. Melville Broughton pushed a button on the speaker’s platform. After a dramatic pause, the generator began spinning inside what was then the first hydroelectric plant to be built in North Carolina in a decade.
Morris-Knudson Co. of Boise, Idaho, was contractor for the project and located its offices in downtown Sylva’s Carolina Hotel. The then-remote communities of Glenville, Tuckasegee and East LaPorte saw their populations swell to the size of small cities with the workers’ arrival, and a rail connection between Sylva and East LaPorte was used to transport material for the project.
When this newspaper reported on the Thorpe Plant’s 50th anniversary in October 1991, that story also revisited Thorpe’s dedication day.
“For Gov. Broughton and the crowd of spectators standing outside that day, the Glenville project symbolized American determination to protect democracy in the world.”
The impetus for the plant was a fireside chat delivered in to the American public by President Franklin D. Roosevelt on Dec. 29, 1940.
“We must be the great arsenal of democracy,” Roosevelt said, calling for “a miracle of production in this country, to support those nations fighting the Axis powers.”
Its installed capacity is rated at 15,500 kilowatts, and Thorpe’s average annual generation is 84,850 megawatt hours, which is enough energy to power 6,425 average homes for one year.
Power plants measure their generating capacity in watts, kilowatts and megawatts. A kilowatt is 1,000 watts, and a megawatt is 1,000,000 watts. In measuring a power plant’s output, the capacity in watts is used over a period of time and is measured in watt (or kilowatt or megawatt) hours. For example, a 60-watt light bulb consumes 60 watt hours of electricity if left on for one hour and 600 watt hours if burned for 10 hours. Lighting uses very little power when compared to heating and air conditioning, which can consume 10 kilowatt hours for each hour of use.
|
