NC0004774_SOC Quarterly Report_20200730

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�C ENERGY
July 24, 2020
Via Overnight Mail
WQROS
MIOORESVILLE REGIONAL OFFICE
Corey Basinger
Mooresville Regional Office Regional Supervisor
North Carolina Department of Environmental Quality
Division of Water Resources
Water Resources - Water Quality Regional Operations
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Bob Sledge
North Carolina Department of Environmental Quality
Water Quality Permitting Program
Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
James Wells
Vice President
Environmental, Health and Safety
Programs & Environmental Sciences
526 South Church Street
Charlotte, NC 28202
[phone]
Subject: Report Under Special Order by Consent — EMC SOC WQ S 18-004
Duke Energy Carolina, LLC — Buck Steam Station
NPDES Permit NC0004774
Quarterly Progress Report for 2nd Quarter 2020
Dear Messrs. Basinger and Sledge:
On behalf of Duke Energy Carolinas, LLC (DEC), I am submitting to you the Buck Steam Station
Progress Report summarizing the work and activities undertaken with respect to closure of coal
ash surface impoundments as required by the Buck Steam Station NPDES Permit NC0004774
Special Order by Consent (SOC), SOC No. S18-004 Section 2.c.2).
As required by the SOC, I certify under penalty of law that this document and all attachments were
prepared under my direction or supervision in accordance with a system designed to assure that
qualified personnel properly gather and evaluate the information submitted. Based on my inquiry
of the person or persons who manage the system, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and belief,
true, accurate, and complete. I am aware that there are significant penalties for submitting false
information, including the possibility of fine and imprisonment for knowing violations.

Messrs. Basinger and Sledge
July 24, 2020
Page 2
Please direct any questions concerning the Buck Steam Station NPDES Permit NC0004774 SOC
No. S 18-004 to Steve Cahoon at [phone].
Sincerely,
James Wells
Vice President, Environment, Health & Safety
Programs and Environmental Sciences
Duke Energy
Attachment
Buck Steam Station Quarterly Progress Report
CC: Richard Baker, Duke Energy
Robert Wylie, Duke Energy
Steve Cahoon, Duke Energy
Dale Wooten, Duke Energy
Paul Draovitch, Duke Energy
Matt Hanchey, Duke Energy
Shannon Langley, Duke Energy
Randy Hart, Duke Energy

NPDES PERMIT NC0004774
SPECIAL ORDER BY CONSENT EMC SOC WQ S18-004
QUARTERLY EXCAVATION PROGRESS REPORT
BUCK STEAM STATION
1 U LY 24, 2020

Background and Summary
On July 12, 2018, Duke Energy Carolinas, LLC (DEC) and the North Carolina Environmental Management
Commission entered into a Special Order by Consent - EMCSOC WQS18-004 (SOC) applicable to the Buck
Steam Station (Buck). This report is submitted in accordance with Section 2.c.2) of the SOC. In compliance
with Section 2.c.2), this report summarizes the work and activities undertaken with respect to decanting
work and closure of coal ash surface impoundments at Buck. The quarterly reports are due no later than
the last day of January, April, July, and October for the duration of the SOC, once the decanting process has
begun.
Buck was once a six -unit coal-fired generating station located on the Yadkin River in Rowan County, NC. The
plant began operation in 1926 with two units, added a unit in 1941, another unit in 1942, and the final two
units in 1953. At its peak, the generating facility had a capacity of 440 megawatts. Units 1 and 2 retired in
1979, Units 3 and 4 retired in 2011, and Units 5 and 6 were retired in 2013. The coal plant has been
demolished through a combination of implosion and mechanical removal of plant structures. The site is
now home of the new Buck Combined Cycle Plant, a 620-megawatt natural gas facility. The combined cycle
plant came on-line in late 2011.
The approximately 150-acre Ash Basin system at Buck consists of three Basins. The Basins are designated as
Primary Pond (also referred to as Basin 2 with 57.5 acres), the Additional Primary Pond (also referred to as
Basin 1 with 71 acres), and the Secondary Pond (also referred to as Basin 3 with 21.5 acres). Basin 1 contains
approximately 3.6 million tons of ash, Basin 2 contains approximately 2.0 million tons of ash, and Basin 3
contains approximately 864,000 tons of ash. An ash fill area also exists, containing approximately 263,000
tons of ash.
Buck was chosen on October 5, 2016, as an ash beneficiation site required by NC House Bill 630. NC House
Bill 630 requires that 300,000 tons of ash from the site be beneficiated to specifications appropriate for
cementitious products each year. NC House Bill 630 also requires that sites with ash beneficiation products
shall be closed no later than December 31, 2029. Excavation of ash from the Buck site for beneficial use will
occur over multiple years. Construction activities began in April 2017. Ash removed from the site will be
beneficiated by SEFA, with whom Duke Energy has entered into an agreement to process and sell all the
usable ash from the Buck Ash Basins for use in the concrete industry. Construction, startup, and
performance testing is scheduled to be completed in Q4 2020. Continuous ash delivery will begin in Q4
2020 to feed the STAR facility operated by SEFA, until all ash in the basins have been recycled, which is
estimated to be complete in 2035. Basin activities have commenced, including temporary haul road and
screening pad construction, as well as ash -screening activities.
Buck: 2

Decanting Status
In compliance with this SOC, Duke Energy initiated design and procurement efforts in Q3 2018 for a
decanting water treatment system at Buck. Purchase Orders were awarded in Q4 2018 for the civil pad and
electrical infrastructure installations, as well as a Purchase Order for the water treatment supplier.
Wastewater flows were removed from the basin on February 7, 2019. Following installation and
commissioning of the decanting water treatment system, mechanical decanting of the basin commenced
on March 27, 2019. Duke Energy provided advanced notice for the projected start date of decanting to
NCDEQon December 20, 2018, as required bythe NPDES Permit, and written notification for the Initiation of
Decanting per the SOC on February 20, 2019. Decanting was completed on March 2, 2020. Following
completion of decanting, the project entered the dewatering phase. Duke Energy continues to dewater the
ash basin as needed to support the ash basin closure and ash beneficiation activities.
Buck: 3