Duke Energy plans to retire its Asheville, N.C., coal-fired power plant in four to five years and modernize its generation and transmission system in western North Carolina and upstate South Carolina — reducing environmental impacts, improving system reliability and minimizing long-term costs to customers.
The plan's major components include retiring the 376-MW Asheville coal power plant, investing about $750 million to build a 650-MW natural gas-fired power plant and installing solar power generation at the site — one of the first combinations of its kind.
The plan includes investing about $320 million to build a transmission substation near Campobello, S.C., and connect it to the Asheville power plant with a new about 40-mile, 230-kilovolt (kV) transmission line. It also includes upgrading and rebuilding additional electrical infrastructure such as transmission lines and distribution substations.
Electricity demand in Duke Energy Progress' Asheville service area has doubled over the last four decades. The region currently must import about 400 MW of power during peak demand periods to ensure system reliability. The region's power demand is also forecast to grow by about 15 percent over the next decade.
In addition, Duke Energy's Asheville coal plant is one of the company's few "must run" power plants, meaning it must operate to maintain reliability, even when it's not economical.
This results in higher fuel costs that are passed on to North Carolina and South Carolina customers each month in their electric bills.
The new gas power plant will be able to rapidly ramp up and down to meet the region's voltage and power demand needs as they change throughout the day.
The gas plant's combined-cycle technology will capture and convert exhaust heat into additional electricity, and is considered one of the most efficient power plant designs available.
At today's natural gas prices, the gas plant would be about 35 percent less expensive to operate than the existing coal plant, saving customers money.
Even with its expected higher operating levels, the gas plant is estimated to have lower environmental impacts than the coal plant. (Final amounts will be determined after the company receives necessary environmental permits.)
· Sulfur dioxide is estimated to be reduced by about 90 to 95 percent.
· Nitrogen oxide is estimated to be reduced by about 35 percent.
· Mercury is completely eliminated.
· Water withdrawals are estimated to be reduced by 97 percent.
· Water discharges are estimated to be reduced by 50 percent.
Carbon dioxide emissions will be reduced by about 60 percent, on a per-MW hour basis, due to the efficiency of the new gas plant and the fact that natural gas burns more cleanly than coal.
The new gas plant also will help reduce carbon dioxide emissions across Duke Energy's Carolinas power plant fleet.
Closing the Asheville coal plant and building a gas plant will make it unnecessary to invest in 126 MW of oil-fired generation units, to meet peak demand, and other capital investments that were planned for 2019.
Duke Energy is working with the local natural gas distribution company to upgrade an existing natural gas pipeline to serve the gas plant with a firm fuel supply.
Duke Energy will continue to move forward with removal of existing coal ash at the site, and permanent closure of the site's ash basins.
The new transmission line and related upgrades, required for overall system reliability, will provide a more robust pathway to move additional electricity to the region to efficiently meet growing customer demand.
The power plant and electric transmission projects will create a peak construction workforce of about 800 jobs in the 2017-2019 timeframe, and generate significant local property tax revenues when brought in-service.
Based on current Buncombe County tax rates, property taxes from the gas power plant are estimated to increase between 35 and 40 percent after the site is modernized.