NC0001422_Proposed Temperature Compliance Shedule_20161209

DUKE
ENERGY.
PROGRESS
December 5, 2016
Mr. Jeffrey O. Poupart
NCDEQ-DWR, Water Quality Permitting Section
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Duke Energy Progress, LLC.
L. V. Sutton Energy Complex NPDES Permit NC0001422
Proposed Temperature Compliance Schedule
Dear Mr. Poupart:
L. V. Sutton Energy Complex
801 Sutton Steam Plant Rd
Wilmington, NC 28401
o: 910.341.4750
f: 910.341.4790
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DEC 0 9 2016
Water Quality
Permitting Section
As required by the existing NPDES permit for the L.V. Sutton Energy Complex, Duke Energy Progress,
LLC (Duke Energy) hereby submits this proposed temperature standard compliance schedule. Section
A(26) of the NPDES permit requires the following: "the facility shall develop the plan for compliance with
the State temperature standard and submit the plan to the Division within 1 year from the effective date of
the permit. The plan shall contain milestones and specific action items. After the plan is approved by the
Division, it will become an enforceable part of the permit."
As Duke Energy has previously documented to the Department of Environmental Quality (DEQ), including
most recently in the July 2016 NPDES permit renewal package, both the temperature within the subject
facility's cooling pond and upstream within the Cape Fear River are occasionally in excess of the 32°C
state temperature standard. However, even with the higher temperatures typical of a thermal wastewater
discharge and characteristic of the natural local background conditions, the aquatic community within the
Sutton cooling pond has been successfully managed as a destination sport fishery since the construction
of the cooling pond in 1972.
There are several pathways available for Duke Energy to pursue that will assure the thermal discharge
continues to be in compliance with the state temperature standard. Duke Energy's preferred path
forward is a continuation of the existing thermal mixing zone. The current NPDES permit contains an
existing temperature mixing zone which extends downstream of Outfall 001 within the Cape Fear River.
The DEQ has supported the validity of this mixing zone by including it in the most recent NPDES permit,
which regulates the cooling pond as a newly declared "water of the state". As documented in the renewal
application, Duke Energy believes that the appropriate origin of that mixing zone remains the discharge
point of heated wastewater from the plant, regardless of the fact that DEQ has shifted the temperature
compliance point from outfall 001 to outfall 008. Therefore the existing permitted mixing zone includes
the entirety of the cooling pond.

';-i
L. V. Sutton Electric Plant NPDES Permit NC0001422'
Proposed Temperature Compliance Schedule
To substantiate this request, Duke Energy requests the opportunity to demonstrate, via data collection
and/or modeling that the existing mixing zone continues to meet state and federal requirements. North
Carolina regulations allow the DEQ to establish mixing zones on a case -by case basis as long as
discharges meet specified criteria. Specifically discharges must not 1) result in acute toxicity to aquatic
life, 2) result in offensive conditions, 3) produce undesirable aquatic life, or 4) endanger public health or
welfare. Duke Energy believes that the thermal discharge from Sutton Plant thoroughly meets this
criteria, as demonstrated throughout the 44 year operating history of the cooling pond and its successful
management as a public fishery.
Duke Energy is also aware that DEQ may require a full 316(a) variance demonstration, and/or a technical
analysis of cooling alternatives. To accommodate for that possibility, Duke Energy requests that the DEQ
allow a compliance schedule for temperature that aligns with the schedule already provided for 316(b)
program study requirements. There are numerous points of overlap which would occur between a
comprehensive thermal variance demonstration and the required impingement and entrainment
demonstrations. The 316(b) regulation requires Duke Energy to conduct feasibility and cost evaluations
of entrainment reduction technologies (including closed -cycle cooling retrofits), as well as economic and
non -water quality impacts. Those would include evaluations of impacts to the power system, social cost
and benefits (such as impacts to recreational fisheries), and evaluations of water consumption for each
entrainment reduction technology. Duke Energy also believes that there is significant overlap in the
316(b) definition of a close cycle recirculating system (CCRS), which may directly inform how thermal
discharges into a cooling pond should be regulated.
Due to the complexity of issues that must be evaluated and the importance of obtaining regulatory agency
concurrence throughout the process, Duke Energy proposes the following compliance schedule:
Due Date
Action required
6 months from DEQ
Duke Energy will hold consultation meetings with DEQ to further discuss
approval of
regulatory options and the path forward.
compliance schedule
9 months from DEQ
Submit Water Quality Monitoring Status Report. This report must specifically
approval of
include a discussion of any water quality monitoring activities performed or
compliance schedule
planned to characterize the existing impact of temperature on the cooling pond.
If DEQ or Duke Energy has determined that monitoring plans require DEQ
approval, those materials will be supplied as part of this report.
24 months from DEQ
Submit Interim Report on actions taken to comply with temperature standard.
approval of
This report should include an interim update on any monitoring that has been
compliance schedule
approved by the DEQ. It should also include the status of any technological
evaluation being performed.
DEQ approval of
Submit NPDES permit application with sufficient data for DEQ to develop
compliance schedule
applicable effluent limits to regulate the temperature discharge from outfall 008.
+ 4.5 years
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L. V. Sutton Electric Plant NPDES Permit NC0001422
Proposed Temperature Compliance Schedule
Duke Energy requests that the compliance schedule include a condition stating that at any time, Duke
Energy may submit an application for permit modification. Any compliance milestones due after Duke
Energy submits an application should be suspended.
Duke Energy appreciates the DEQ's review of this proposed compliance schedule. As staff is aware, the
Sutton cooling pond is managed as a public fishery and has been since construction was completed in
1972. Duke Energy has maintained and operated the cooling pond in a manner that has not only
provided for its primary intended purpose, to support the generation of electric power for public use, but
Duke Energy's active management of the cooling pond has provided a substantial recreational benefit to
the community. The North Carolina General Assembly, the DEQ and Duke Energy have recognized the
mutual benefit of encouraging public use in a waterbody constructed and actively used as a cooling pond
at the Sutton Plant. Duke Energy looks forward to evaluating these important issues with the DEQ and
developing a path forward that continues to best serve the resource and citizens of North Carolina.
If there are any questions, please contact Mr. Kent Tyndall, Environmental Professional and ORC-B for
the L. V. Sutton Energy Complex; phone [phone] or e-mail [e-mail]; or
Ms. LeToya Ogallo, Environmental Specialist at our North Carolina Regional Office, phone (919) 546-
6647 or email [e-mail].
`7 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 forgathering 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
fines and imprisonment for knowing violations."
Sincerely,
Jesse E. Huntley II.
Station Manager
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