SPENCER — At a ribbon-cutting ceremony Thursday, officials said the close partnership between Duke Energy and Rowan County helped make the new Buck Combined Cycle Station possible.
Combined cycle technology, which uses both natural gas and steam to generate electricity, has higher efficiency, more flexibility and fewer emissions than traditional coal units.
Dhiaa Jamil, chief generation officer for Duke Energy, said he is proud to see one of the company’s most efficient natural gas plants built on the same site as one of its first fossil fuel stations.“Rowan County and Buck Steam Station have played a key role in what Duke Energy is today,” Jamil said.
State and local officials toured the plant, located on the Yadkin River outside Spencer, on Thursday afternoon. It is the company’s first combined cycle station in the Carolinas.
The station began commercial operations in November 2011, three years after preparations began in 2008.
Brett Carter, president of Duke Energy North Carolina, thanked RowanWorks Economic Development and other organizations in the county for helping to make the project a success.
“We’re proud to be partnered with Rowan County, and we’re going to continue that partnership,” he said.
In 2008, the county awarded Duke Energy incentives to expand the station, giving the company $840,000 back from its property taxes annually for 10 years.
Chad Mitchell, chairman of the Rowan County Board of Commissioners, said the county is glad to have Duke Energy as one of its corporate citizens.
“What you see behind you is a testament and a success story to the cooperation between government and private industry,” Mitchell said. “It’s an amazing thing when it works well.”
RowanWorks chairman Robert Van Geons said the long-standing relationship between Duke Energy and Rowan County is a great example of a working “public-private partnership.” He named several other investments the company has made in the economy and the community. “Thank you for all that you do to support economic development here,” Van Geons said.
In 1926, Buck Steam Station began generating electricity for the area with two coal-fired units, which were shut down last year. Two more units built in 1979 are planned to go offline a few years from now.
Duke Energy aims to retire 3,800 megawatts of its coal power by 2015, including more than 1,000 megawatts retired last year and early this year. Jamil said the Buck station project, which was estimated to cost $600 million, was completed under budget and ahead of schedule. It employed hundreds of workers during construction, and the station now operates with about 30 employees.
While Duke Energy has raised its rates to cover the cost of the project, spokeswoman Erin Culbert said it will create long-term savings for the company and its customers.The combined cycle plant also is more environmentally friendly than coal units.
The new station uses less than 5 percent of the water that two coal-fired units draw. Because its cooling towers use ambient air for steam condenser cooling, no heated water is discharged back into the Yadkin River.
The station burns low-sulfur natural gas, which reduces its sulfur dioxide emissions. Exhaust gases pass through a system that removes a majority of nitrous oxide from the air, along with significant amounts of carbon monoxide and volatile organic compounds.
The combined cycle station can generate 620 megawatts of electricity, which is twice the capacity of Buck Steam Station’s original 369 megawatt rating.It was built to run only when the demand for energy increases. But Duke Energy has been operating it more regularly because of the low cost purchasing fuel from Piedmont Natural Gas.
“Natural gas is at a record low price, and it will be there for a very long time. This particular site has been a workhorse already since the day it came online,” Jamil said. “It couldn’t have come at a better time.”
The station employs between 25 and 30 people. A 20-inch pipeline supplies natural gas to the site. At full load, each gas turbine consumes about 76,400 pounds per hour of natural gas. That’s roughly equivalent to a gas grill-sized tank of natural gas per second. The Buck Combined Cycle Station can generate 620 megawatts of electricity, or twice the capacity of Buck Steam Station’s original 369 megawatt rating.
The station’s cooling towers use ambient air for steam condenser cooling, which minimizes intake and discharge impacts to the Yadkin River. Maximum flow requirements from the Yadkin River are about 5 percent of the water used by two of Buck’s coal-fired units. No heated water is discharged to the Yadkin River.
How It Works
A natural gas combined cycle generating facility efficiently combines two energy production processes — gas combustion turbines and a steam turbine — to convert natural gas fuel to electricity.
First, natural gas is burned in two combustion turbines to heat compressed air. The expanding air turns a turbine with mechanical energy that is converted to electric power by the generator.
The hot exhaust gases are then routed through two 93-foot-tall heat recovery system generators, which heat water to produce steam. The steam turns a steam turbine generator to create additional electricity.