By David Meade
Work on the new 750-Megawatt Natural Gas Combined-Cycle plant at the Duke Energy W. S. Lee Steam Station site is about three quarters complete while excavation and removal of coal ash now includes a second basin.
According to Duke Energy Corporate Communications spokesperson Danielle Peoples, both projects are progressing as expected and remain on time and on budget.
Duke is currently in the process of excavating 1.4 million tons of coal ash from an inactive ash basin and an ash fill area at the W. S. Lee site and transporting the material to a fully lined landfill in Homer, Ga.
The project has been underway since May of 2015 and is about fourty-four percent completed, according to Peoples. It is expected to be finished by the end of 2017.
As of Jan. 2017, approximately 800,000 tons of coal ash has been moved from the inactive ash basin. A new lined sediment basin has been constructed at the removal site to manage stormwater in the ash fill area.
Work has also recently begun to remove coal ash from a secondary ash fill basin located across the road from the current removal site.
Both sites are located in close proximity to the road, the original Lee Steam Station and the new Combined Cycle plant under construction, making the area even more congested.
Trucks will be entering the roadway from both sides of Lee Steam Plant Road.
Construction has been underway on a new access road which includes a truck scale and truck wash, similar to those being used at the inactive ash removal site during the last year.
Work at the new site will result a new traffic pattern with trucks entering Lee Steam Plant Road from the opposite side of the road. Additional road signange and the implementation process to coordinated truck drivers entering the highway.
The current loading plan calls for 70 truckloads per day to move ash out of the new excavation area.
This is in addition to approximately 95 truckloads per day that have been coming out of the inactive ash basin for the past year.
The new excavation site has approximately 256,000 tons of ash to be removed.
Peoples said there is about 600,000 tons of ash remaining.
Excavation and removal from the inactive ash basin (1,100,147 tons) and the ash fill area (256,000 tons) is expected to be completed by the end of the year.
Duke is planning to construct a lined landfill on the property for the remaining ash located on the back side of the property.
Approximately 2.2 million tons of coal ash remaining on the site will be moved to an on-site lined landfill once permitted and constructed.
“We had intended to submit our landfill application to DHEC in October of 2016, “ Peoples said. “After further dicussion with DHEC it was decided we needed to have additional seasons of ground water data to submit with our application.”
Peoples said Duke is now looking at submitting the application for the lined landfill in October of 2018.
Work on the new W. S. Lee Combined-Cycle plant is now about 77 percent complete as of January, Peoples said.
The estimated cost of the W. S. Lee Steam Combined Cycle project is approximately $700 million, including financing, gas interconnect and electric transmission interconnect costs, according to Peoples
According to information provided by Duke Energy of the Carolinas, the project is part of a comprehensive, long term plan to add new generation, modernizing the fleet, maintian a diverse fuel portfolio and manage customer costs while delivering a highquality, reliable power supply.
A new dedicated gas pipeline and associated metering and compression equipment is being installed on the existing Duke Energy Carolinas and Piedmont Natural Gas rights-of-way to serve the new combined-cycle plant.
The gas pipeline is about one mile in length and branches off from the Transcontinental mainline located nearby.
According to Peoples, the project is progressing as expected and plans are to bring the new unit online in November of this year.
All major equipment rail deliveries have been received and most are already on their foundations. This includes combustion turbines, steam turbines, heat recovery steam generators and generator step-up transformers.
System turnover from Flour to the Duke commissioning team is now in progress.
The new switchyard is energized and plans are to bring permanent power into the site in early February, People said. Final connection to the gas line will also be done soon.
The overall project is about seventy-seven percent complete as of January, she said.
The project represents a substantial long-term investment by Duke Energy Cariolinas in the facility and surrounding community.
Construction and related activities are expected to add several million dollars to the local tax base and economy. Once construction is complete, about 40 full time workers will be needed to operate the plant.
The original W. S. Lee Steam Station, which was retrofited from coal to natural gas, will also remain in service as a back up unit, according to Peoples.
A steam turbine (Unit 3) at the facility was converted from coal to natural gas in 2015. Two combustion steam turbines were installed in 2007.
The turbines help in the startup of the Oconee Plant, primarily during peak periods.