Duke Energy Corp. announced a plan this week to significantly expand a large natural gas-fired peaking facility in North Carolina to serve as a proving ground for a single-cycle combustion turbine that Siemens Corp. wants to build and test there.
Duke has submitted plans to the North Carolina Utilities Commission for the expansion that includes Siemens as the engineering, procurement and construction contractor for the project.
"This serves as an advantage for Duke to meet customer need, but to Siemens as a test facility in the field," said Duke spokesman Rick Rhodes.
The utility is projecting that 400 MW of peaking energy will be needed to meet customer demand in the Carolinas by 2024.
Siemens would build a single 400 MW turbine at Duke's Lincoln County Combustion Turbine generation site in three phases, Rhodes said. The parts would be manufactured at its' 452,000 square-foot facility in Charlotte, NC. Pending regulatory approval, construction could begin in mid-2018, with testing to begin in 2020 in order to meet projected demand by 2024.
The new turbine would be a "first of a kind" unit with "considerably larger output,” said Rhodes. The Lincoln County facility houses 16 gas-fired simple-cycle combustion turbines that each average roughly 75 MW of output. The Lincoln County site is fed by Piedmont Natural Gas, which Duke acquired last year, via a Transcontinental Gas Pipe Line lateral.
According to Siemens, the turbine would feature "super-efficient" internal cooling features, "evolutionary" 3D blading, an advanced combustion system and "state-of-the-art manufacturing technologies." If approved, the proposed unit would be the most efficient combustion turbine in the Duke fleet, offering 25% more efficiency than those in operation at the Lincoln County facility.
Duke billed the agreement as a way to lower customer costs, boost the regional economy, lower emissions and provide the "flexible peaking power needed to complement intermittent solar energy resources" in its generation fleet.
The Lincoln County facility was built in 1995. The 746-acre site near Denver, NC, about 25 miles from downtown Charlotte, is considered ideal for the expansion, the company added. If the turbine is constructed, the site's output would increase from 1,200 MW to 1,600 MW.
Gas-fired power generation has been on the rise across the country in recent years, thanks in part to surging shale production. But as more renewables have been added to the grid as well, gas has become even more important to serve as capacity backup.
Many of the new facilities proposed or under construction use combined-cycle turbines, which take heat from a gas unit for utilization in a steam unit that generates more power. While those plants can be turned up to power fast, single-cycle facilities are quicker to turn on and cheaper to operate. Single-cycle plants are often used to provide peak load or standby service.
Siemens Corp. is the U.S. subsidiary of Germany-based Siemens AG. Duke's electric utilities and infrastructure unit serves 7.5 million customers in six states in the Southeast and Midwest and it has 49,300 MW of generating capacity.