The SGT6-8000H gas turbine from Siemens Energy Inc. is an engineering marvel. Consisting of more than 7,000 parts, the turbine has a gross power output of 274 megawatts—the equivalent of 855 Chevrolet Corvettes. At 280 tons, it weighs a little more than a fully fueled and fully loaded Airbus 340 jet with 300 passengers on board. The turbine is 36 feet long and 13.8 feet in diameter, and yet its parts are machined to tolerances of just a few thousandths of an inch.
But perhaps the most amazing aspect of the turbine is where it’s made—right here in the United States. To be specific, the turbine is made at Siemens’ newly expanded assembly plant in Charlotte, NC.
The Charlotte facility was originally built by Westinghouse in 1969 to make steam turbines for nuclear plants. Siemens took over the factory in 1997. In October 2010, Siemens broke ground on a $350 million expansion project to double the size of the already sprawling complex, from 550,000 square feet to 1 million square feet. The expansion officially opened just 13 months later, in November 2011, and is expected to be at full production by April 2012, turning out 36 to 48 gas turbines annually.
Last summer, I got a behind-the-scenes look at the facility, and it is truly state of the art.
Operating 24/7, the facility produces and services generators, steam turbines and gas turbines for 60-kilohertz electric power plants in the United States, Canada, Mexico, Brazil, Saudi Arabia, Korea and other countries. (Generators and turbines for 50-kilohertz power plants, the standard in Europe, are made at Siemens’ assembly plant in Berlin.)
These are big assemblies. The largest generator made at the plant weighs 600 tons! During my tour, I passed boring machines that were bigger than my house. These machines were custom-made for Siemens and cost some $4 million each.
Despite the massive size of the parts, the machine tools at the facility hold very tight tolerances. During my tour, I passed a generator rotor that was 25 feet long. Slots running the length of the rotor were cut to a tolerance of ±0.005 inch.
Meeting those tolerances is more than just a function of the machine tool. The temperature and humidity in the facility are carefully controlled. Even a 1-degree change in ambient air temperature could cause such big parts to expand or contract enough to throw off the machining process.
Massive machine tools weren’t the only high-tech wizardry on display. The plant boasts fiber-optic lasers capable of penetrating steel to a depth of 0.5 inch. Laser-guided robots picked and placed large steel laminations with the effortlessness of a Las Vegas blackjack dealer.
When designing the addition, Siemens engineers took advantage of the blank slate to rethink their turbine manufacturing process. Applying lean manufacturing principles to the new layout, engineers reduced cycle time by 30 percent compared with an older Siemens facility in Hamilton, ON, which is slated to close early this year. Engineers also reduced the number of times a turbine moves by 20 percent and decreased overall travel distance for a turbine by 60 percent.
As big as the facility is, it’s environmentally friendly. The plant’s office space is gold-certified for Leadership in Energy and Environmental Design (LEED), while the manufacturing space is LEED silver.
The plant’s manufacturing gear may be awe-inspiring, but people are just as critical to the operation. The plant employs more than 1,200 people, some 400 of whom were hired in 2011 alone. Siemens is expected to hire an additional 600 people in the near future. (The expansion is also expected to create approximately 2,000 additional indirect jobs at suppliers and service providers.)
Prospective employees shouldn’t expect to just walk in and get hired, however. Indeed, for every 50 blue-collar manufacturing jobs at the plant, Siemens gets some 2,000 applicants. Of those, perhaps 200 make the first cut. To train and evaluate job candidates, Siemens enlisted the help of the nearby Central Piedmont Community College and the North Carolina Department of Labor.
To train its future engineers, Siemens and Duke Energy, the local electric utility, donated almost $10 million to the engineering department at the University of North Carolina—Charlotte. The funds are being used to develop a curriculum and research center dedicated to energy production.