BC_DRAFT_ClosureOptionsAnalysis_20181025

('DUKE
�' ENERGY
October 25, 2018
Ms. Sheila Holman
Assistant Secretary for Environment
North Carolina Department of Environmental Quality
1611 Mail Service Center
Raleigh, North Carolina 27699-1611
Subject: Belews Creek ash basin closure options analysis
Dear Ms. Holman:
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
526 S. Church Street
Mail Code: SCUP
Charlotte, NC 28202
[phone]
Duke Energy is providing information in response to the North Carolina Department of
Environmental Quality's requests on September 13 and October 8, 2018, to submit
preliminary updates to the closure options analysis, groundwater modeling and net
environmental benefit analysis for the Belews Creek Plant. These studies represent a
key portion of the engineering and environmental evaluation the company has
performed to develop closure plans that balance a variety of considerations.
This submittal provides the updated closure options analysis and groundwater
modeling. The net environmental benefit analysis will be forthcoming as soon as
possible and by November 15, 2018.
Duke Energy remains committed to safely closing ash basins and welcomes input from
DEQ and the public to best balance the various environmental, community and cost
tradeoffs involved.
Sinc rely,
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
cc: Jim Wells, Duke Energy
Dave Renner, Duke Energy
Randy Hart, Duke Energy
Ed Mussler, DWM
Jon Risgaard, DWR
Andrew Brooks, DEMLR
Bill Lane, NCDEQ General Counsel

Belews Creek Steam Station Ash Basin Closure Options Analysis
Summary Report
This summary report (Report) presents the Closure Options evaluation for the ash basin located at Duke
Energy Carolinas, LLC's (Duke Energy's) Belews Creek Steam Station, located in Stokes County, North
Carolina. The Closure Options Evaluation involved developing ash basin closure strategies and evaluating
these options relative to one another to determine which option to advance to more detailed
engineering and closure plan development. The strategies discussed in the Closure Options Evaluation
are representative of the range of possible approaches for basin closure, and do not constitute final
closure plans as described in N.C. Gen. Stat. sec. 130A-309.214(a)(4). Final closure plans will be
submitted in 2019, as required by law, supported by detailed engineering designs and any necessary
updates to groundwater modeling and related analysis.
Duke Energy developed programmatic guidance for the closure analysis effort in early 2016 to provide
fleet -wide consistency to ash basin closure plan development . Duke Energy developed a relative
weighting and scoring system with input from the National Ash Management Advisory Board (NAMAB).
Using this system, Duke Energy evaluated and scored the alternatives using an options analysis
framework designed to identify the best solution that balances environmental protection, cost, schedule
and local community impacts. It is noted that internal working draft versions of these 2015-2017
options analyses for Allen, Belews Creek, Cliffside, Marshall, Mayo, and Roxboro were provided to
NCDEQ at its request in May and June 2018.
The 2016 internal working draft options analysis identified closure -in -place as the preferred solution for
Belews Creek that is protective of the environment, safely closes the ash basin, minimizes the other
associated risks, and was the least cost to the customers. A permit -level design was developed for that
option in 2016. The company then paused that work, pending determination that the site would meet
the requirements for a low -risk impoundment classification pursuant to CAMA, as amended by House
Bill 630. Duke Energy has completed those requirements at the Belews Creek site for a low -risk
classification and now has updated this analysis.
Earlier this year, a subsurface investigation was performed within the ash basin area that is normally
submerged in order to evaluate the thickness of ash at select locations. The results of this investigation
indicated that most of the areas investigated had ash thicknesses less than five feet, which is
significantly less than had been previously estimated. Based on this additional information, a new
hybrid closure option (designated Option 6) was developed which is a refined version of the previous
hybrid (Option 2). Option 6 closes almost half the ash basin by closure -by -removal and the other half by
closure -in -place and provides for the management of stormwater to minimize scouring of the channel,
flooding impacts to downstream properties including infrastructure (road and railroad). Based on the
updated ash thickness information, the northern edge of the hybrid cover was reconfigured to use
compacted ash stabilization approach which provided cost savings and reduction in uncertainty with
regards to constructability. The updated Closure Options Analysis includes this new hybrid option in the
analysis..
Summary — Page 1

In addition, prior alternatives that had been listed as Option 2 (Hybrid), Option 3 (Closure -by -removal
with a new landfill inside the basin footprint), and Option 5 (Closure -by -removal to an off -site landfill)
were removed from consideration from the Options Analysis for reasons of optimized design, excessive
schedule/cost, and availability of on -site landfill space.
SITE BACKGROUND
The Belews Creek Steam Station is located in Stokes County, North Carolina along Belews Lake, a man-
made lake constructed on Belews Creek in the early 1970s. Belews Creek Steam Station is a two -unit,
coal-fired power generation facility that is one of the largest steam plants in the Carolinas, with a
capacity of 2,240 megawatts. Belews Creek Steam Station has been in service since 1974. Belews Creek
operates one impoundment for storing wet -sluiced ash, which is referred to as the Active Ash Basin (Ash
Basin). In 1984, Belews Creek converted to a dry fly ash handling system, but the ability to sluice fly ash
to the ash basin remained available. In accordance with the requirements in CAMA, the units were
converted to a 100% dry fly ash disposal system in March 2018 and a dry bottom ash disposal system in
May 2018. The most significant volume of wastewater streams placed into the ash basin is FGD
wastewater. The volume of wastewater discharge to the ash basin has been reduced over the years
owing to less runtime for generating units since the units are reserved to provide electricity during peak
periods. The ash basin includes two embankment structures functioning as dams. These include the Ash
Basin Dam situated on the north side of the ash basin and the Roadway Embankment situated on the
east side of the ash basin at Pine Hall Road. The ash basin dam and roadway embankment are regulated
by NCDEQ's Dam Safety Program and have been assigned the State ID STOKE-116. Figure 1 presents the
ash basin and the dams.
Summary— Page 2

Figure 1. Ash Basin
CLOSURE OPTIONS
For the Belews Creek Steam Station, under the direction of Duke Energy, AECOM developed the
following conceptual closure options that remain under evaluation:
1. Closure in -Place
4. Closure -by -Removal: Onsite Landfill Outside the Ash Basin
6. Hybrid Closure (2018) - Closure -by -Removal for areas under water and Closure in -Place for the
ash delta/higher elevation portion. Reduced closure footprint within the ash basin with a
stabilized ring buttress of compacted ash for stability, and downstream flood control via a
retention/staging feature within the excavated portion.
Option 1 consists of leaving the ash material within the ash basin, which would be capped with an
infiltration barrier/cap system meeting the requirements of the Federal Coal Combustion Residuals
Summary — Page 3

(CCR) Rule and N.C. Coal Ash Management Act (CAMA). Figures A1A and A1B present the closure -in
place concept for Option 1.
Option 4 consists of excavating all ash materials from the ash basin and placing these ash materials in a
new lined On -Site Landfill to be built within the wooded area south of Pine Hall Road within Duke Energy
property. This 83-acre landfill would be capped with an infiltration barrier/cap system meeting the
requirements of the Federal CCR Rule and CAMA. Figures A4A and A413 present the closure -by -removal
concept for Option 4.
Option 6 is an updated version of the previous Option 2, but was developed with the insights gained
from the 2018 subsurface investigation and downstream flood control needs due to pond closure. It can
be considered an optimized version of Option 2. The hybrid ash closure area would be capped with an
infiltration barrier/cap system meeting the requirements of the Federal CCR Rule and CAMA. Figures
A6A and A613 present the closure -in -place concept for Option 6.
Options earlier evaluated but not carried forward included: Option 2 (hybrid) — replaced by Option 6;
Option 3 (closure -by -removal with new landfill in basin footprint); and Option 5 — closure -by -removal
with off -site landfill.
Tables 1, 2, and 3 of this report represent a tabulated summary of each evaluated closure option,
estimated quantities of ash and soil materials associated with each closure option, and a more detailed
overview of each closure option presented.
Attachment A of this report includes figures depicting conceptual level plan drawings and cross
sections/details for each closure option.
The figures included in Attachment A are as follows:
• Figure A1A—Option 1 Closure -In -Place Plan View
• Figure A1B — Option 1 Closure -In -Place Profile and Section Views
• Figure A4A — Option 4 Removal to New On -site Landfill Outside the Ash Basin Plan View
• Figure A413 — Option 4 Removal to New On -site Landfill Outside the Ash Basin Profile and Section
Views
• Figure A6A — Option 6 Hybrid (2018) Closure Plan View
• Figure A613 — Option 6 Hybrid (2018) Closure Profile and Section Views
• Figure A7 — Details
Attachment B includes rough order of magnitude (ROM) cost estimates for each closure option.
Attachment C contains the scoring matrix which summarizes the composite scores of the various closure
options, the assumptions of which are outlined in Table 3 for each particular option.
Summary — Page 4

METHODOLOGY
A scoring matrix was prepared to provide consistent evaluation of closure options for each of their
various site locations. This scoring evaluation tool can be found in Attachment C and considers the
following primary criteria:
• Environmental Protection and Impacts
• Cost
• Schedule
• Regional Factors
• Constructability
Rough Order of Magnitude Costs
A rough order of magnitude (ROM) Class 5 cost estimate was prepared for each of the closure options,
based on information and quantities developed during the conceptual design activities. The estimated
costs include construction, permitting, engineering design, post -construction O&M, and groundwater
monitoring. A tabulated summary of the preliminary closure cost estimates is provided below:
Current Estimates (October 2018)
Option
Closure Option
Estimated
Estimated O&M
Construction Cost
Cost (30 Years)
1
Closure in -Place
$143,000,000
$59,000,000
4
Removal: Onsite Landfill Outside
$478,000,000
$32,000,000
the Ash Basin
6
Hybrid Closure (2018)
$134,000,000
$40,000,000
Option 6: Hybrid Closure (2018) option has the lowest estimated construction cost based on a
reasonable balance between ash excavation volume, final cover area, and geotechnical stabilization
needs compared to other options. Detailed tabulated ROM cost estimates are included in Attachment
B.
Schedule
Within the scoring evaluation, estimates of the length of time required to initiate closure activities and
the anticipated construction duration are provided for each option. For the Closure -By -Removal option
(4), a substantial amount of effort is anticipated for site preparation and dewatering activities, which
dictates the longer estimated initiation times.
A major driver in the estimated construction durations is the assumed material excavation/movement of
1 M CY/year; therefore, the Closure -By -Removal option has longer construction durations, due to the
requirement to move of all ash materials, compared to the Hybrid and Closure -In -Place options where
Summary — Page 5

material movement quantities are less and assumed capping rates (50 ac/year) would overlap schedule -
wise with excavation.
Evaluation Criteria
This options analysis was developed as a decision -making tool to assist in selection of closure options
when multiple methods are allowed under applicable regulations. The intent was to develop a decision
framework that used weighted scorings to balance environmental factors, cost, and the safety of
workers and the public. The options analysis incorporates Duke Energy's obligation as a regulated utility
to ensure that its closure decisions are protective of the environment and communities, while also being
prudent from a cost-effectiveness perspective.
The analysis considered multiple aspects in each criterion, including surface water, groundwater, air
emissions, greenfield disturbance, construction duration, imported soil needs, transportation and noise
impacts, stormwater management, long-term maintenance needs and post -closure monitoring.
The company then combined these elements to provide a weighted sum for each criterion using the
following weights: environmental considerations (30%), cost (35%), schedule (15%), regional/community
factors (15%) and constructability (5%.) Duke Energy placed primary emphasis on environmental factors
and cost, which were approximately equal in weight. When considering all of the criteria and associated
weightings, the environmental considerations have a slightly higher weight than cost with the inclusion
of certain regional/community factors (transportation impact, noise impact, view impact) which are
effectively environmental considerations.
The scoring matrix provided in Attachment C scores each option on a scale of 0 (least favorable) to 10
(most favorable) for each of the specified criteria. The scores for each option are then summed based
on specified criterion weighting, resulting in an overall weighted score for each option. The results of
the scoring evaluation for the Belews Creek closure options are summarized below:
Scoring Summary (October 2018
Criterion
Option
1
4
6
Environmental Protection and
Impacts
1.99
2.13
2.21
Cost
2.72
0.70
3.29
Schedule
1.50
0.00
1.20
Regional Factors
1.17
0.03
1.16
Constructability
0.50
0.30
0.30
Total Score
7.88
3.16
8.16
Summary — Page 6

DISCUSSION
The options analysis finds relatively similar rankings for environmental considerations, such as impacts
to groundwater, surface water, and avoidance of greenfield disturbance. The analysis incorporates the
latest groundwater modeling at Belews Creek that demonstrates groundwater near the basin responds
similarly for several decades in all closure options evaluated. The current modeling does not incorporate
capping or removal of other potential sources, subject to different legal requirements. If these additional
areas were included, the closure would take longer, cost more, and potentially disturb more habitat. The
most effective step the company can take to improve groundwater is to safely decant the free water
from the ash basin, which will occur in any closure approach.
In terms of duration of work and closure time (i.e., initiation time and construction duration), the
Closure -In -Place option (#1) would be expected to be completed in 9 years and both hybrid options (#6)
in 10 years, while the Closure -By -Removal option (#4) would be expected to take up to 16 years and
would extend beyond the current CAMA deadline of 2029 and possibly the CCR deadline of 2034. It
remains in our Options Analysis despite this for full transparency of the alternative.
Other aspects the company considered are regional impacts to the community related to imported soil
needs, transportation and noise.
The Closure -By -Removal option is more than triple the estimated cost of the Closure -In -Place options
and causes other unnecessary community impacts with little compelling environmental benefit. While
long-term modeling indicates is a quicker reduction in the boron plume within the immediate vicinity of
the basin footprint for the Closure -By -Removal scenario, compared to the Closure -in -Place scenario, the
modeled concentrations at downstream points are nearly identical for all the closure options at each
evaluated point in time. Moreover, the quicker reduction is partially offset by the fact that the modeled
improvement is delayed in the Closure -By -Removal scenario, compared to the Cap -in -Place scenario,
due to the extended construction time. In any event, the minor change in modeled plume size, within
the immediate vicinity of the basin footprint, is not enough to justify the cost of the Closure -by -Removal
scenario —particularly when the impact and improvement do not materially affect neighbors or other
potential receptors
The Hybrid Closure option (#6) and the Closure -in -Place option rank the highest, respectively. The
Hybrid Closure option is estimated to have lower capital and O&M costs. It also removes the dam and
brings the potential to beneficially reuse the dam material for closure. Utilizing the excavated portion of
the basin footprint in this option enables retention/staging of stormwater in large rain events to provide
protection of downstream features in the tributary of the Dan River. These factors combined make the
Hybrid Closure (Option #6) the preferred closure option.
CONCLUSION
Based on the concept designs for the selected closure options and evaluation of the criteria established
(environmental protection/impacts, cost, schedule, regional factors and constructability), Closure -In -
Place (Option #1) and Hybrid Closure (Option #6) were identified as the options that best balance the
various considerations associated with basin closure. The Hybrid Closure (Option 6) is estimated to
have lower capital and O&M costs and thus is the selected closure option for Belews Creek.
Summary — Page 7

Table 1 — Closure Options Summary
Ash Basin Closure Options Evaluation
Belews Creek Steam Station
Duke Energy
Description
• Install stormwater controls
• Install free water decanting and water treatment system
• Decant free water
• Perform interstitial dewatering of ash material as needed to provide
stable working surfaces
• Regrade ash basin waste boundary and construct closure cap.
• Balance of cover material required from dam lowering and onsite
borrow area.
• Minimal dam removal and restore disturbed areas.
• Groundwater corrective action and long-term monitoring pursuant to
CAMA/CCR
• Install stormwater controls.
• Install free water decanting and water treatment system
• Decant free water
• Perform interstitial dewatering of ash material as needed to provide
stable working surfaces and removal of ash.
• Design, permit, and construct a lined landfill outside the ash basin
footprint within the site property.
• Excavate the ash from the basin, place in the landfill, cap using the
soil from the dam (in addition to geosynthetics).
• Complete dam removal and restore excavated areas to stable and
non -erodible condition.
• Groundwater corrective action and long term monitoring pursuant to
CAMA/CCR.
• Install stormwater controls
• Install free water decanting and water treatment system
• Decant free water
• Perform interstitial dewatering of ash material as needed to provide
stable working surface and removal of ash
• Construct ring buttress to stabilize the slope
• Excavate ash, and place excavated ash material within the Hybrid
ash closure area.
• Install closure cap system
• Removal of dam
• Groundwater corrective action and long-term monitoring pursuant to
CAMA/CCR.

Table 2 — Quantity Summary
Ash Basin Closure Options Evaluation
Belews Creek Steam Station
Duke Energy
Item
Volume (CY)
Area (AC)
21) Surface
31) Surface
Existing Ash
Ash Basin Area (for engineering purposes)
NA
270
NA
In Place Ash
9,975,833
270
NA
Ash Basin Dam
1,100,000
15
NA
1-Foot Overexcavation
435,600
270
NA
Option 1: Closure in Place
Closed contained ash
9,975,833
270
275
Approximate cut/fill volume
2,000,000
NA
NA
1-Foot Overexcavation
0
0
NA
Dam soil cut volume
360,000
NA
NA
2 ft soil cover
887,333
270
275
Option 4: Onsite Landfill Outside the Excavated Ash
Basin
Closed contained ash
9,975,833
83
88
Ash excavation volume
9,975,833
NA
NA
1-Foot Overexcavation
435,600
270
NA
Landfill baseliner system (2-ft soil + synthetics)
282,981
NA
88
Landfill cover system (2-ft soil + synthetics)
282,981
NA
88
Dam soil cut volume
1,100,000
NA
NA
Option 6: Hybrid Option 2018
Closed contained ash
9,975,833
144
146
Ash excavation volume
2,600,000
NA
NA
1-Foot Overexcavation
203,280
126
NA
Ash stabilization area (cut sluiced ash and recompact
ash)
1,100,000
NA
NA
2 ft soil cover
471,093
NA
146
Dam soil cut volume
1,100,000
NA
NA

Subject
Table 3.1 — Option 1 Overview: Closure in Place
Ash Basin Closure Options Evaluation
Belews Creek Steam Station
Duke Energy
Description — Option 1
1. Install stormwater controls
2. Install free water decanting and water treatment system
3. Decant free water
4. Perform interstitial dewatering of ash material as needed to provide
stable working surfaces
5. Regrade ash basin waste boundary and construct closure cap.
6. Balance of cover material required from dam lowering and onsite
borrow area.
7. Minimal dam removal and restore disturbed areas.
8. Groundwater corrective action and long-term monitoring pursuant to
CAMA/CCR
1. Install stormwater run-on controls to divert stormwater from the ash
basin where possible.
2. Design and install temporary water treatment system to manage
decanting, interstitial dewatering, and (contact) stormwater.
3. Decanting & treatment of free water.
4. Regrade the close -in -place area to direct stormwater to the existing
permitted outfall.
5. Grade the ash surface to promote positive drainage. Limited ash
excavation and stacking within the ash basin are anticipated. Cut and
fill volumes are expected to be balanced. Estimated total cut and fill
volume is about 2.0 million cubic yards in the water covered area and
ash delta. Localized dewatering may be needed at certain locations to
support access and future placement of the cover system.
6. Start partial removal of dam. Final volume of soil to be removed from
the dam is estimated to be about 360,000 cubic yards.
7. Construct closure cap over ash basin area using soils from dam
excavation and onsite borrow area. Total soil cover soil volume is
estimated to be about 890,OOOcubic yards based on a 2-ft thick soil
cover system. The total soil cover 3-D surface area is 275 acres. Total
2-D footprint of the closure area is 270 acres. Total in place ash
volume as of July 31, 2018 is 11,971,000 tons (9,975,833 cubic yards).
8. Decommission temporary wastewater treatment facility.
9. Complete minimal dam removal and tie-in with closure cap.
10. Groundwater corrective action and long term monitoring pursuant to
CAMA.

Subject
Description — Option 1
1. Air emissions off -site (based on miles driven) — NA
2. Air emissions on -site (based on gallons of fuel consumed) from closure
implementation — this will be best option as construction work is limited.
3. Avoidance of greenfield disturbance — On -site borrow area only.
1. Capital costs = $143 MM
2. Long-term operations maintenance and monitoring = $2.OMM annual.
1. Initiation time (to begin ash removal) = 30 months (includes
design/permitting and dewatering).
2. Design and permitting = 12 months.
3. Construction = 76 months
4. Post -closure = 30 years.
5. Total duration = 106 months
1. In place closure being unlined.
2. NPDES permit modifications.
3. Plan or potential for beneficial reuse of site — none.
4. Imported soil needs — Reuse partial dam removal soil.
5. CCR beneficial reuse - None
6. Transportation impact (based on miles driven) — No offsite miles.
Onsite limited within ash basin footprint — minimal construction
compared to other options.
7. Noise impact due to on -site activity (based on proximity of neighbors) —
very little.
8. Visual impact (based on final height of storage facility, land uses within
the viewshed) — better than current conditions (i.e. almost none).
1. Relative to other options, this one has easier construction.
2. Stormwater management within basin.
3. No high excavations within the ash.
4. Dewatering will include free water removal and treatment and (as
needed to provide a stable working surface) interstitial pore water
removal and treatment as part of ash excavation and cover system
placement
1. Relatively limited construction compared to other options.
2. Economical option compared to landfill disposal.
3. Can be safely executed using typical ash pond closure construction
methods.
4. Less chance for schedule delays.
1. Larger footprint of unlined area.
2. Cover slopes are generally on the flatter side, resulting in more
maintenance needs.
3. Dam remains a regulated dam in place following completion of closure
construction.
In

Table 3.4 — Option 4 Overview: Removal - Onsite Landfill Outside the Ash Basin
Ash Basin Closure Options Evaluation
Belews Creek Steam Station
Duke Energy
Subject Description — Option 4
1. Install stormwater controls
2. Install free water decanting and water treatment system
3. Decant free water
4. Perform interstitial dewatering of ash material as needed to provide
stable working surfaces
5. Construct a lined landfill outside the ash basin footprint within the site
property.
6. Excavate the ash from the basin, place in the landfill, cap using the soil
from the dam (in addition to geosynthetics).
7. Complete dam removal and restore excavated areas to stable and non -
erodible condition.
8. Groundwater corrective action and long term monitoring pursuant to
CAMA/CCR.
1. Install stormwater run-on controls to divert stormwater from the ash
basin and industrial landfill areas where possible.
2. Design and install temporary water treatment system to manage
decanting, interstitial dewatering, and (contact) stormwater.
3. Decanting & treatment of free water.
4. Removal & treatment of interstitial pore water in ash material as needed
to provide stable working surfaces during excavation within the closure -
by -removal area.
5. Construct a lined landfill outside the ash basin footprint within the site
property. Landfill 2D area is 83 acres.
6. Excavate the ash from the ash basin and haul to the landfill.
Excavation volume estimated to be 9.9 million cubic yards.
7. Start partial dam removal.
8. Place ash in the landfill and cap. Total ash contained in landfill is
960,000 cubic yards (intent is to expand and contain the full amount of
ash). Total soil cover soil volume is estimated to be 280,000 cubic
yards based on a 2-ft thick soil cover system (in addition to
geosynthetics). The total soil cover 3-D surface area is 88 acres.
9. Complete dam removal and restore excavated areas to stable and non -
erodible condition. Final volume of soil to be removed from the dam is
estimated to be 1,100,000 cubic yards.
10. Complete partial dam removal and tie-in with closure cap.
11. Groundwater corrective action and long term monitoring pursuant to
CAMA/CCR.
1. Air emissions off -site (based on miles driven) — NA

Subject
Description — Option 4
2. Air emissions on -site (based on gallons of fuel consumed) from closure
implementation — this will have the most impact due to hauling needs
among the onsite options.
3. Avoidance of greenfield disturbance — This impacts onsite industrial
greenfield area.
1. Capital costs = $478 M M
2. Long-term operations maintenance and monitoring = $1.1 MM annual.
3. Avoided costs — Off -site hauling ash, costs managed through
minimizing material handling.
1. Initiation time (to begin ash removal) = 54 months (includes dewatering
and design and permitting)
2. Design and permitting = 24 months.
3. Construction = 138 months
4. Post -closure = 30 years.
5. Total duration = 192 months which would require a variance or
extension of deadline under CAMA
1. Siting/permitting of new landfill (landfill location assumed to be suitable
but not fully studied
2. NPDES permit modifications
3. Constructing landfill in greenfield (industrial) area near to the Belews
Lake and some water supply wells.
4. Plan or potential for beneficial reuse of site — Restore to nature
5. Imported soil needs — Reuse dam removal soil. Potential additional soil
needs to meet hydraulic conductivity requirements and cap landfill..
6. CCR beneficial reuse - None
7. Transportation impact (based on miles driven) — No offsite miles.
Onsite hauling across Pine Hall Road.
8. Noise impact due to on -site activity (based on proximity of neighbors).
9. Visual impact (based on final height of storage facility, land uses within
the viewshed) — Need to consider Landfill Viewshed.
1. Relatively manageable construction option.
2. Stormwater management within basin and outside as well (landfill,
hauling).
3. Excavation can be in layers and safe.
4. Dewatering will include free water removal and treatment and (as
needed to provide a stable working surface) interstitial pore water
removal and treatment as part of ash excavation and cover system
placement.
1. Closure by removal
2. Complete dam removal
1. Landfill takes up greenfield space.
2. Crossing Pine Hall Road for 11 yrs.
E.

Table 3.6 — Option 6 Overview: Hybrid Closure Option 2018 (Removal for areas
under water and Closure in Place for the ash delta) - Reduced Closure Footprint
Within the Ash Basin
Subject
Ash Basin Closure Options Evaluation
Belews Creek Steam Station
Duke Energy
Description — Option 6
1. Install stormwater controls
2. Install free water decanting and water treatment system
3. Decant free water
4. Perform interstitial dewatering of ash material as needed to provide
stable working surfaceslnstall stabilized ash wedge as needed
5. Excavate the selected ash areas that were mainly under water at the
start of the project, and place excavated ash material within the Hybrid
ash closure area.
6. Install closure cap system
7. Develop storm water staging and retention features
8. Removal of dam
9. Groundwater corrective action and long-term monitoring pursuant to
CAMA/CCR.
1. Install stormwater run-on controls to divert stormwater from the ash
basin where possible.
2. Design and install temporary water treatment system to manage
decanting, interstitial dewatering, and (contact) stormwater.
3. Decanting & treatment of free water. Removal & treatment of interstitial
pore water in ash material as needed to provide stable working
surfaces during construction within the closure -in -place and closure -by -
removal areas. Excavate and re -compact ash along the hybrid stack
tie-in with hybrid in -place sluiced ash perimeter to serve as a ring
buttress.
4. Excavate the selected ash areas that were mainly under water at the
start of the project. Stack the excavated ash on top of the existing ash
delta, away from the excavation slope initially. Excavation volume
estimated to be 2.6 million cubic yards.
5. Construct small new perimeter berm at one location for the hybrid
closure area for long-term .
6. Start dam removal. Final volume of soil to be removed from the dam is
estimated to be 1.1 million cubic yards.
7. Grade closure area and construct closure cap using soils from dam
excavation. Total cut/fill volume is estimated to be about 2,600,000
million cubic yards. Total soil cover soil volume is estimated to be
500,000 cubic yards based on a 2-ft thick soil cover system. The total
soil cover 3-D surface area is 146 acres. Total 2-D footprint of the
closure area is 144 acres. Total in place ash volume as of July 31,
2018 is 11,971,000 tons (9,975,833 cubic yards).

Subject
Description - Option 6
8. Complete dam removal and restore excavated areas to stable and non -
erodible condition.
9. Complete I dam removal and tie-in with closure cap.
10. Groundwater corrective action and long term monitoring pursuant to
CAMA.
1. Air emissions off -site (based on miles driven) - NA
2. Air emissions on -site (based on gallons of fuel consumed) from closure
implementation - this will be second best option based on construction
work, along with Option 5.
3. Avoidance of greenfield disturbance - On -site borrow area only.
1. Capital costs = $134 MM
2. Long-term operations maintenance and monitoring = $1.3 MM annual.
3. Avoided costs - Off -site hauling ash, costs managed through
minimizing material handling.
1. Initiation time (to begin ash removal) = 36 months (includes dewatering
and design/permitting, and is a function of the DMM wall construction).
2. Design and permitting = 18 months.
3. Construction = 88 months
4. Post -closure = 30 years
1. In place closure portion being unlined.
2. NPDES permit modifications.
3. Plan or potential for beneficial reuse of site - Partially restore to nature
and use for hybrid closure footprint.
4. Imported soil needs - Reuse dam removal soil.
5. CCR beneficial reuse - None
6. Transportation impact (based on miles driven) - No offsite miles.
Onsite limited within ash basin footprint.
7. Noise impact due to on -site activity (based on proximity of neighbors) -
little or minimal.
8. Visual impact (based on final height of storage facility, land uses within
the viewshed) - minimal.
1. Construction can be more challenging than Options 1 and 4.
2. Stormwater management within basin.
3. High excavations within the ash and overfilling ash delta. Need
stabilization.
4. Dewatering will include free water removal and treatment and (as
needed to provide a stable working surface) interstitial pore water
removal and treatment as part of ash excavation and cover system
placement.
1. Footprint reduction.
2. Most economical option.
3. Complete dam removal.
4. Provides for water staging/retention of 100 yr storm event which
minimizes downstream impacts
1. Footprint with unlined area remains partially.
E.

Subject Description — Option 6
2. Long term stability due to the ponded ash slopes will need to be
addressed with an ash stabilization area. Compacted ash perimeter
buttress ring inside sluiced ash area proposed.

Attachment A

4.
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18 IN MIN.
STANDARD ASH BASIN CLOSURE CAP SYSTEM
N.T.S
GEOCOMPOSITE
DRAINAGE LAYER
FLEXIBLE
MEMBRANE
LINER (FML)
2 FT
MIN.
i -
ALTERNATE ASH BASIN CLOSURE CAP SYSTEM
N.T.S
Nf)TF-
EITHER STANDARD ASH BASIN CLOSURE AND CAP SYSTEM OR ALTERNATE ASH BASIN CLOSURE AND CAP SYSTEM WILL BE USED IN:
• IN -PLACE CLOSURE OPTION
• 2015/2016 HYBRID CLOSURE OPTION
• 2018 HYBRID CLOSURE OPTION
LANDFILL COVER SYSTEM WILL BE DEVELOPED BASED ON SELECTED LINER SYSTEM
GEOCOMPOSITE
DRAINAGE LAYER
FLEXIBLE MEMBRAN
LINER (FML) �`� ram■ �'�' - -�- r�r■ - - �' �r
COMPACTED SOIL LAYER 2 FT MIN.
(KV<1x10-7 CM/SEC) - - - -
SUBGRADE \\\ EX. SUBSURFACE SOILS /\\\ \\\� 5 FT. MIN.
\\\
/ ORSOIL FILL
SEASONAL HIGH
GROUNDWATER '
STANDARD LANDFILL LINER SYSTEM
GEOCOMPOSITE
DRAINAGE LAYER
FLEXIBLE MEMBRANE LINER (FML)
NOTE:
N.T.S
ASH MATERIAL
PREPARED SUBGRADE 1 FT MIN.
GEOSYNTHETIC CLAY LINER � .
(GC L)
SUBGRADE EX. SUBSURFACE SOILS, 5 FT. MIN
OR SOIL FILL
SEASONAL HIGH
GROUNDWATER
ALTERNATE LANDFILL LINER SYSTEM
N.T.S
EITHER STANDARD LANDFILL LINER SYSTEM OR ALTERNATE LANDFILL LINER SYSTEM WILL BE USED IN:
• ONSITE LANDFILL INSIDE EXCAVATED ASH BASIN
• ONSITE LANDFILL OUTSIDE THE EXCAVATED ASH BASIN
COVER AND LINER SYSTEM DETAILS
DUKE ENERGY
BELEWS CREEK ASH BASIN CLOSURE
BELEWS CREEK, NORTH CAROLINA
FOR BELEWS CREEK STEAM STATION
DUKE SCALE: N.T.S.
fi� DWG TYPE:
OB
2891
vow. ENErbfm%%/® DATE: 110178/2018
_ FILENAME: FIGURE A7 com DWG SIZE DRAWING NO.
DES: NP
DFTR: NP
CHKD : KK
ENGR: KK/NP
APPD : KK
REVISION
0
F71
0
6 1 2 3 1 ITENTHS 10 20 30
ANSI D
22.0"x 34.0"
FIGURE A7
X

Attachment B

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
AZCOM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule&CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
�!�
CALCULATION SHEET
Preliminary Promect Costs Sheets
ActNeAsh Basin
Close -in -Place
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Close -in -Place Cost Estimate for CCR Surface Impoundment
Option 1: Closure -in -Place
Kula Kulasingam
10/24/2018
Nick Popko—ki
Belews Creek Active Ash Basin -- OPTION 1: Closure -in -
Place
Closure & Post Closure Cost Summary
Close -in -Place Tasks
Cost
(2018 Dollars)
Mobilization / Site Prep
$5,246,207
Dewatering / Earthwork / Subgrade Prep.
$37,043,254
Closure System Construction
$23,322,024
Stormwater Management / E&S Controls / Site Restoration
$46,077,023
Contingency (25%)
$27,922,127
Engineering Support (Design and CQA)
$2,900,000
Total Closure Cost of CCR Impoundment =
$142,510,635
Post -Closure Tasks
Cost
(2018 Dollars)
Groundwater Monitoring
$14,424,990
Operations & Maintenance (O&M)
$28,153,980
Contingency (25%)
$10,644,743
Engineering Costs (10%)
$5,322,371
Total Post -Closure of CCR Impoundment =
$58,546,084
Total Closure & Post -Closure of CCR Impoundment Cost = $201,056,719
Preliminary based on information available as of 10/24/2018
10/25/2018 1 of 6

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
A.-mCM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule&CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Active Ash Basin
Close -in -Place
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Close -in -Place Costs
Option 1: Closure -in -Place
Kula Kulasingam
10/24/18
Nick Popkowski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL AREA TO BE RESTORED (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
20,000
MOBILIZATION/
SITE PREP
DEWATERING /
EARTHWORK /
SUBGRADE PREP
CLOSURE SYSTEM
CONSTRUCTION
CLOSE -IN -PLACE ESTIMATED COSTS
INSTALLED
IMPOUNDMENT
TASK
ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
MOBILIZATION 1 SITE PREP
Mob/Demob & insurance: (1 % of Total EPC Bid Price
1
MOBILIZATION
LS
1
$1,134,540
$1,134,540
includes administration (mtgs, health & safety, trailer,
phone/fax/electricity, temporary facilities, utilities, roll off
boxes, waste disposal, and cleanup).
2
ABANDON OUTLET STRUCTURES / PIPING
LS
1
$994,112
$994,112
Abandon existing outlet structures and piping.
3
REMOVAL & FILTRATION OF FREE WATER
MONTHS
30.0
$103,919
$3,117,555
Initiation time
DEWATERING 1 EARTHWORK 1 SUBGRADE PREP
4
REMOVAL & TREATMENT OF PORE WATER WITHIN ASH
MONTHS
76.0
$225,832
$17,163,254
Construction time
5
RING DRAIN INSTALLATION
L.F.
20,000
$58
$1,160,000
Linear feet around the proposed cap.
Quantity of earthworK (cut -to -fill) using existing ash to
6
ASH REGRADING TO ESTABLISH CROWN
CY
2,000,000
$9.24
$18,480,000
achieve min. 2 % slope prior to installation of closure
system. Quantity calculated using AutoCAD.
7
PERIMETER DITCH / TEMP. DIVERSION BERM GRADING
L.F.
20,000
$12
$240,000
Linear feet around the perimeter of impoundment.
CLOSURE SYSTEM CONSTRUCTION
8
18" PROTECTIVE COVER SOIL
CY
653,400
$13
$8,494,200
18 inches of common soil placed over closure by removal
area (obtained off -site)
9
6" TOPSOIL
CY
217,800
$13
$2,831,400
6 inches of topsoil (obtained offsite) placed over total
impoundment area.
10
COMPACTED CLAY
CY
0
$15
$0
Not used
11
FLEXIBLE MEMBRANE LINER (FML)
SQ. FT.
11,761,200
$0.42
$4,939,704
Alternate Cap System Only: Flexible membrane liner
placed over total impoundment area.
10/25/2018 2 of 6

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
MCM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule& CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Active Ash Basin
Close -in -Place
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Close -in -Place Costs
Option 1: Closure -in -Place
Kula Kulasingam
10/24/18
Nick Popkowski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
7TOTAL AREA TO BE RESTORED (AC)
270
7AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
20,000
CLOSE -IN -PLACE ESTIMATED COSTS AL
INSTALLED
IMPOUNDMENT
TASK ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
12 GEOCOMPOSITE DRAINAGE LAYER
SQ. FT.
11,761,200
$0.60
$7,056,720
Alternate Cap System Only: Geocomposite drainage layer
placed over total impoundment area.
13 GEOSYNTHETIC CLAY LINER (GCL)
SQ. FT.
0
$0.72
$0
not used
10/25/2018 3 of 6

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
MCM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule& CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Active Ash Basin
Close -in -Place
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Close -in -Place Costs
Option 1: Closure -in -Place
Kula Kulasingam
10/24/18
Nick Popko—ki
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
7TOTAL AREA TO BE RESTORED (AC)
270
7AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
20,000
CLOSE -IN -PLACE ESTIMATED COSTS
INSTALLED
IMPOUNDMENT
TASK
ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
STORMWATER MANAGEMENT 1 E&S CONTROLS 1 SITE RESTORATION
14
EROSION AND SEDIMENT CONTROL
ACRE
270
$2,000
$540,000
Assume total area to be restored will require site erosion
STORMWATER
and sediment control.
MANAGEMENT/
E&S CONTROLS /
Assume rip -rap lined stormwater conveyance channels and
SITE
15
STORMWATER MANAGEMENT / CHANNELS / LET -DOWNS
L.F.
60,000
$742
$44,520,000
rip rap lined let -downs off of cap. Quantity assumed at 3
RESTORATION
times perimeter
16
SEED / FERTILIZE / MULCH
ACRE
270
$3,767
$1,017,023
Assume total area to be restored will be mulched, fertilized,
and seeded.
CONTINGENCY 1 ENGINEERING SUPPORT
CONTINGENCY/
ENGINEERING
17
CONTINGENCY(25%)
LS
1
$27,922,127
$27,922,127
SUPPORT
18
ENGINEERING SUPPORT (DESIGN AND CQA)
LS
1
$2,900,000
$2,900,000
POST -CLOSURE
Annual groundwater monitoring costs for each CCR
POST -CLOSURE
19
GROUNDWATER MONITORING
ANNUAL
30
$480,833
$14,424,990
impoundment are based on current groundwater
monitoring system
Annual O&M costs are $3475/acre/yrforthe total closed
20
OPERATIONS & MAINTENANCE (O&M)
ANNUAL
30
$938,466
$28,153,980
area with cap. Based on Q3 2018 Post Closure
Maintenance data
CONTINGENCY 1 ENGINEEIING COST
CONTINGENCY/
ENGINEERING
21
CONTINGENCY(25%)
LS
1
$10,644,743
$10,644,743
COST
22
ENGINEERING COST (10%)
LS
1
$5,322,371
$5,322,371
TOTAL
$201,056,719
10/25/2018 4 of 6

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
MCM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule& CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Active Ash Basin
Close -in -Place
60482182,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Close -in -Place Costs
Option 1: Closure -in -Place
Kula Kulasingam
10/24/18
Nick Popkowski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
7TOTAL AREA TO BE RESTORED (AC)
270
7AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
20,000
CLOSE -IN -PLACE ESTIMATED COSTS
TASK ITEM
UNIT
QUANTITY
INSTALLED
UNIT COST
IMPOUNDMENT
CLOSURE COST
NOTES
Preliminary based on information available as of 10/24/2018
10/25/2018 5 of 6

PROJECT
PLANT NAME:
CLOSURE TYPE:
SHEET
REV. NO.
A—
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule&CAMA Compliant
Close -in -Place Assumptions
B
SUBJECT
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.
CALCULATION SHEET
Preliminary Promect Costs Sheets
ActiveAsh Basin
Close -in -Place
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Close -in -Place Assumptions
Option 1: Closure -in -Place
Kula Kulasingam
10/24/18
Nick Popko—ki
KEY ASSUMPTIONS
The following key assumptions and limitations are associated with the project design, implementation and performance:
1
The cost estimates were prepared using 2018 dollars and do not include any escalation.
2
A 25% contingency has been included for this cost estimate.
3
Engineering design and CQA cost has been included for this cost estimate based on reasonable assumptions.
4
The unit rate costs are based on data provided by Duke Energy. If no data is available, AECOM supplemented with rates from our experience.
5
Free water removal and treatment was assumed to continue throughout the project initiation period.
6
Interstitial water treatment was assumed to continue until construction is completed.
7
Abandonment of existing structures/piping includes the demolition in -place or bulkheading of existing pipes and inlets/outlet structures, grouting of outlet pipes that extend beyond the limits of waste, and
backfilling of existing structures in -place for the purposes of a close -in -place closure of an impoundment.
8
To establish the minimum top slopes of 2%, assume existing ash will be utilized to establish crown.
9
Cap cross section for the CCR impoundment will consist of flexible membrane liner, geocomposite drianage layer, and 18-inches of protective cover soil (Kv<1x10-5 cm/sec) overlain by 6-inches of topsoidin
10
Common soil for embankment and protective cover soil construction are available onsite and topsoil would come from offsite.
11
Groundwater monitoring costs are for the existing network system. Groundwater monitoring costs do not include costs incurred for any additional well installation. Maintenance costs for wells are include
post-closure O&M costs.
12
O&M costs include, but are not limited to, the monitoring and maintenance/repair of the groundwater monitoring system, cap system, and storm water controls.
13
Statements of Probable Construction Cost prepared by AECOM represent AECOM's judgment as a design professional familiar with the construction industry. It is recognized, however, that neither AECOM
nor the Owner has control over the cost of labor, materials or equipment nor over the contractor's methods of determining the bid price or other competitive bidding, market, or negotiating conditions.
Accordingly, AECOM cannot and does not warrant or represent that proposals, bids or actual construction costs will not vary from any statement of Probable Construction Cost or other estimates or
evaluations prepared by AECOM.
Preliminary based on information available as of 10/24/2018
1
10/25/2018 6 of 6

AXOM
' - ■
PROJECT:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
Bel —Creek
CLOSURE TYPE:
CCR Rule & CAMA Compliant
SHEET:
Cost Summary
REV. NO.:
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Closure by Removal Cost Estimate for CCR Impoundment (Onsite
4- Removal and Landfill
Landfill Outside the Basin)
Outside Basin
Kula Kulasingam
10/24/2018
Nick Popko—ki
Belews Creek Active Ash Basin -- OPTION 4: Removal
with Onsite Landfill Outside the Basin
Closure & Post Closure Cost mary
Clean -Closure Tasks
Cost
(2018 Dollars)
Mobilization / Site Prep / Demobilization
$10,402,154
Dewatering / Excavation / Convey Material
$201,653,522
Onsite Landfill Construction, Disposal and Closure
$150,279,145
Stormwater Management / E&S Controls / Site Restoration
$16,105,840
Contingency (25%)
$94,610,165
Engineering Support (Design and CQA)
$5,000,000
Total Closure Cost of CCR Impoundment =
$478,050,826
Post -Closure Tasks
Cost
(2018 Dollars)
Groundwater Monitoring
$14,424,990
Operations & Maintenance (O&M)
$8,863,290
Contingency (25%)
$5,822,070
Engineering Costs (10%)
$2,911,035
Total Post -Closure of CCR Impoundment =
$32,021,385
Total Closure & Post -Closure of CCR Impoundment Cost = $510,072,211
Preliminary based on information available as of 10/24/2018
10/25/2018 1 of 6

AECMCCR
PROJECT:
IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
Belms Creek
CLOSURE TYPE:
CCR Rule &LAMA Compliant
SHEET:
Closure -by -Removal Costs
REV. NO.:
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Promect Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LASTUPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Closure by Removal Costs: Closure by Removal Cost Estimate for CCR Impoundment (Onsite
4- Removal and Landfill
Landfill Outside the Basin)
Outside Basin
Kula Kulasingam
10/24/18
Nick Popk—ski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL AREA TO BE RESTORED (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
6,000
MOBILIZATION/
SITE PREP/
DEMOBILIZATION
ACHIEVE
CLOSURE -BY -
REMOVAL/
CONVEY
MATERIAL
ONSITE LANDFILL
CONSTRUCTION,
DISPOSAL AND
n ncl 117E
CLOSURE -BY -REMOVAL ESTIMATED COSTS
INSTALLED
IMPOUNDMENT
TASK
ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
MOBILIZATION I SITE PREP I DEMOBILIZATION
Mob/Demob & insurance: (1 % of Total EPC Bid Price)
1
MOBILIZATION / DEMOBILIZATION
LS
1
$3,796,443
$3,796,443
includes administration (mtgs, health & safety, trailer,
phone/fax/electricity, temporary facilities, utilities, roll off
boxes, waste disposal, and cleanup).
2
REMOVAL OF OUTLET STRUCTURES / PIPING
LS
1
$994,112
$994,112
Assume outlet structures and piping will be excavated
and removed.
3
REMOVAL & FILTRATION OF FREE WATER
MONTHS
54.0
$103,919
$5,611,599
Based on Initiation Time
DEWATERING I EXCAVATION I CONVEY MATERIAL
STEP 1: Start dewaterting for Construction time. Based
4
REMOVAL & TREATMENT OF PORE WATER WITHIN ASH
MONTHS
138.0
$225,832
$31,164,856
on Construction Time
Step 2: Assume CCR material must be stockpiled within
impoundment area to decant prior to loading. Done in
5
EXCAVATE ASH FOR CLOSURE -BY -REMOVAL / STOCKPILE ASH
CY
9,975,800
$8.00
$79,806,400
conjunction with Step 1. Decant water collected and
treated along with pore water from Step 1.
EXCAVATE ASH FROM STOCKPILE /LOAD /HAUL ASH (DISPOSE ON-
Step 3: Once material has decanted, CCRs must be
6
SITE)
CY
9,975,800
$8.43
$84,095,994
excavated out of stockpile, loaded on trucks and hauled
to onsite disposal site
7
EXCAVATE / LOAD / HAUL CCR-IMPACTED SOIL (ON -SITE)
CY
871,200
$7.56
$6,586,272
Assume 2 feet of additional material to be removed
over total impoundment area.
8
EXCAVATE / LOAD / HAUL CCR MATERIAL (OFF -SITE LF)
CY
0
$57
$0
Only include if disposing CCRS at an off -site landfill
9
EXCAVATE / LOAD / HAUL CCR-IMPACTED SOIL (OFF -SITE LF)
CY
0
$57
$0
Only include if disposing CCRS at an off -site landfill
ONSITE LANDFILL CONSTRUCTION, DISPOSAL AND CLOSURE
Assume landfill designed and constructed in
accordance with CAMA and CCR Rules. Cost includes
10
CONSTRUCT ON -SITE LANDFILL AND ASSOCIATED COMPONENTS
AC
85
$803,245
$68,275,825
landfill construction and all associated components,
including: liner system, leachate management,
stormwater management, access roads, closure
system and all associated components,etc.
10/25/2018 2 of 6

Amm—CM
PROJECT:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
Belms Creek
CLOSURE TYPE:
CCR Rule &LAMA Compliant
SHEET:
Closure -by -Removal Costs
REV. NO.:
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
PreliminarV Promect Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LASTUPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Closure by Removal Costs: Closure by Removal Cost Estimate for CCR Impoundment (Onsite
4- Removal and Landfill
Landfill Outside the Basin)
Outside Basin
Kula Kulasingam
10/24/18
Nick Popkmski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL AREA TO BE RESTORED (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
6,000
CLOSURE -BY -REMOVAL ESTIMATED COSTS
INSTALLED
IMPOUNDMENT
TASK ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
yLVJVI"
Place, spread and compact in thin lifts dewatered ash
DISPOSE/SPREAD/COMPACT ASH AND CCR-IMPACTED MATERIALS
11
CY
10,847,000
$7.56
$82,003,320
and CCR-impacted materials excavated from closure -by
FROM CLOSURE -BY -REMOVAL AREA IN ON -SITE LANDFILL
removal area.
12 ON -SITE LANDFILL CLOSURE SYSTEM
AC
85
$0
Included with landfill construction under line item 10
10/25/2018 3 of 6

Amm—CM
PROJECT:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
BelewsCreek
CLOSURE TYPE:
CCR Rule & CAMA Compliant
SHEET:
Closure -by -Removal Costs
REV. NO.:
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
PreliminarV Promect Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LASTUPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Closure by Removal Costs: Closure by Removal Cost Estimate for CCR Impoundment (Onsite
4- Removal and Landfill
Landfill Outside the Basin)
Outside Basin
Kula Kulasingam
10/24/18
Nick Popkowski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL AREA TO BE RESTORED (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
6,000
CLOSURE -BY -REMOVAL ESTIMATED COSTS AL
INSTALLED
IMPOUNDMENT
TASK
ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
STORMWATER MANAGEMENT I E&S CONTROLS I SITE RESTORATION
10
PERMANENT RIPRAP STORMWATER CHANNELS
L.F.
7,250
$50
$362,500
Assume If x ftwidex 1 ftthick, 145 pcf riprap
n
lined stormwatewater channels.
STORMWATER
11
SITE EROSION AND SEDIMENT CONTROL
ACRE
270
$2,000
$540,000
Assume total area to be restored will require site
MANAGEMENT /
erosion and sediment control.
E&S CONTROLS /
12
BACKFILL AND REGRADING
CY
873,000
$13.00
$11,349,000
Assume 2 feet of additional soil material (obtained
SITE
onsite) graded over total closure -by -removal area.
RESTORATION
Assume 6-inches of top soil needed (obtained offsite)
13
TOPSOIL
CY
218,250
$13.00
$2,837,250
to establish vegetative stabilization over total closure -by -
removal area.
14
SEED /FERTILIZE /MULCH
ACRE
270
$3,767
$1,017,090
Assume total area of disturbance will be mulched,
fertilized, and seeded.
CONTINGENCY I ENGINEERING SUPPORT
CONTINGENCY/
15
CONTINGENCY(25%)
LS
1
$94,610,165
$94,610,165
ENGINEERING
SUPPORT
16
ENGINEERING SUPPORT (DESIGN AND CQA)
LS
1
$5,000,000
$5,000,000
POST -CLOSURE
POST -CLOSURE
Annual groundwater monitoring costs for each CCR
15
GROUNDWATER MONITORING
ANNUAL
30
$480,833
$14,424,990
impoundment are based on current groundwater
monitoring system.
Annual O&M costs are $3475/acre/yr for the total
16
OPERATIONS & MAINTENANCE (O&M)
ANNUAL
30
$295,443
$8,863,290
closed area with cap. Based on Q3 2018 Post Closure
Maintenance data.
CONTINGENCY I ENGINEERING COST
CONTINGENCY/
ENGINEERING
17
CONTINGENCY(25%)
LS
1
$5,822,070
$5,822,070
COST
18
ENGINEERING COST (10%)
LS
1
$2,911,035
$2,911,035
10/25/2018 4 of 6

Amm—CM
PROJECT:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
Belms Creek
CLOSURE TYPE:
CCR Rule &LAMA Compliant
SHEET:
Closure -by -Removal Costs
REV. NO.:
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
PreliminarV Promect Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LASTUPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Closure by Removal Costs: Closure by Removal Cost Estimate for CCR Impoundment (Onsite
4- Removal and Landfill
Landfill Outside the Basin)
Outside Basin
Kula Kulasingam
10/24/18
Nick Popkmski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL AREA TO BE RESTORED (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
VOLUME OF ASH IN IMPOUNDMENT (CY)
9,975,800
PERIMETER OF IMPOUNDMENT (L.F.)
6,000
CLOSURE -BY -REMOVAL ESTIMATED COSTS
TASK
ITEM
UNIT
QUANTITY
INSTALLED
UNIT COST
IMPOUNDMENT
CLOSURE COST
NOTES
TOTAL
$510,072,211
Preliminary based on information available as of 10/24/2018
10/25/2018 5 of 6

a COM
/� •' ■
PROJECT
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
PLANT NAME:
Bel —Creek
CLOSURE TYPE:
CCR Rule & CAMA Compliant
SHEET
Closure -by -Removal Assumptions
REV. NO.
B
SUBJECT
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.
CALCULATION SHEET
Preliminary Project Costs Sheets
Ash Basin
Closure by Removal
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
4- Removal and Landfill
Closure by Removal Assumptions:
Outside Basin
Kula Kulasingam
10/24/18
Nick Popk—ski
49 KEY ASSUMPTIONS
The following key assumptions and limitations are associated with the project design, implementation and performance:
1
The cost estimates were prepared using 2018 dollars and do not include any escalation.
2
A 25% contingency has been included for this cost estimate.
3
Engineering design and CQA cost has been included for this cost estimate based on reasonable assumptions.
4
The unit rate costs are based on data provided by Duke Energy. If no data is available, AECOM supplemented with rates from our experience.
5
Free water removal and treatment was assumed to continue throughout the project initiation period.
6
Removal of existing structures/piping includes the excavation and disposal of existing structures within the limits of waste and the bulkheading or grouting of existing outlet pipes that extend beyond the limits
of waste. This will be performed during the Closure -by -Removal of an impoundment.
7
Interstitial water treatment was assumed to continue until construction is completed.
8
Assumed all CCR material excavated must be stockpiled in close proximity to the impoundment to be decanted. After decanting, the material will be excavated, loaded, and hauled to the on -site landfill for
disposal.
9
Costs for onsite landfill construction was based on a per acre basis as provided by Duke.
10
AECOM has assumed an over -excavation of 1 foot is necessary to achieve closure -by -removal conditions.
11
Groundwater monitoring costs are for a reduced groundwater network system as compared to the existing system. Groundwater monitoring costs do not include costs incurred for any additional well
installation. Maintenance costs for wells are included in post -closure O&M costs.
12
O&M costs include, but are not limited to, the maintenance/repair of the groundwater monitoring system and general maintenance of the former CCR impoundment area.
13
Statements of Probable Construction Cost prepared by URS represent URS's judgment as a design professional familiar with the construction industry. It is recognized, however, that neither AECOM nor the
Owner has control over the cost of labor, materials or equipment nor over the contractor's methods of determining the bid price or other competitive bidding, market, or negotiating conditions. Accordingly,
AECOM cannot and does not warrant or represent that proposals, bids or actual construction costs will not vary from any statement of Probable Construction Cost or other estimates or evaluations prepared
by AECOM.
Preliminary based on information available as of 10/24/2018
1
10/25/2018 6 of 6

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
a-COM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule&CAMA Compliant
Cost Summary
B
SUBJECT:
IMPOUNDMENT NAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
PreliminaW Promect Costs Sheets
Ash Basin
Hybrid
60432132,60572891
ACTIVITY:
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6-Hybrid 2018
Kula Kulasingam
10/24/2018
Nick Popk—ski
Belews Creek Active Ash Basin -- OPTION 6: Hybrid
Option 2018
Closure & Post Closure Cost Summary
Closure Tasks
Cost
(2018 Dollars)
Mobilization / Site Prep / Demobilization
$5,815,269
Dewatering / Excavation for Closure -by -Removal / Convey Material
$55,894,382
Dewatering / Earthwork for Close -in -Place
$24,962,248
Closure System Construction
$13,092,022
Stormwater Management / E&S Controls / Site Restoration
$4,825,175
Contingency (25%)
$26,147,274
Engineering Support (Design and CQA)
$4,500,000
Total Closure Cost of CCR Impoundment =
$135,236,370
Post -Closure Tasks
Cost
(2018 Dollars)
Groundwater Monitoring
$14,424,990
Operations & Maintenance (O&M)
$15,015,456
Contingency (25%)
$7,360,112
Engineering Costs (10%)
$3,680,056
Total Post -Closure of CCR Impoundment =
$40,480,614
Total Closure & Post -Closure of CCR Impoundment Cost = $175,716,984
Preliminary based on information available as of 10/24/2018
10/25/2018 1 of 7

10/25/2018 2 of 7

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
w—
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Belews Creek
CCR Rule & CAIM1A Compliant
Hybrid Costs
B
/q
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Pro'ect Costs Sheets
Ash Basin
Hybrid
60432132, 60572391
ACTIVITY :
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6- Hybrid 2013
Kula Kulasingam
10/24/13
Nick Popkowski
BASIS OF THE ESTIMATE
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL AREA TO BE RESTORED (AC)
297
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
IMPOUNDMENT AREA TO BE CLOSED -IN -PLACE (AC)
144
IMPOUNDMENTAREA TO BE CLOSED -BY -REMOVAL (AC)
126
EXISTING ASH VOLUME IN AREA TO BE CLOSED -IN -PLACE (CY)
8,959,400
TOTAL ASH VOLUME FROM CLOSURE -BY -REMOVAL (CY)
1,016,400
TOTAL (FINAL) ASH VOLUME TO BE CLOSED -IN -PLACE (CY)
9,975,800
PERIMETER OF CLOSED IN PLACE IMPOUNDMENT (L.F.)
10,000
LENGTH OF CUT -SLOPE AT CLOSE -IN -PLACE / REMOVAL INTERFACE (L.F.)
2,000
MOBILIZATION/
SITE PREP/
DEMOBILIZATION
DEWATERING /
EXCAVATION FOR
CLOSURE -BY -
REMOVAL/
CONVEY
MATERIAL
DEWATERING /
EARTHWORK FOR
CLOSE -IN -PLACE
HYBRID ESTIMATED COSTS
INSTALLED
IMPOUNDMENT
TASK
ITEM
UNIT
QUANTITY
UNIT COST
CLOSURE COST
NOTES
MOBILIZATION / SITE PREP / DEMOBILIZATION
Mob/Demob & insurance: (1 % of Total EPC Bid Price) includes administration
MOBILIZATION / DEMOBILIZATION
LS
1
$1,080,091
$1,080,091
(mtgs, health & safety, trailer, ph one/fax/electricity, temporary facilities, utilities, roll
off boxes, waste disposal, and cleanup).
REMOVAL OF OUTLET STRUCTURES / PIPING
LS
1
$994,112
$994,112
Assume outlet structures and piping will be excavated and removed.
REMOVAL & FILTRATION OF FREE WATER
MONTHS
36.0
$103,919
$3,741,066
Based on Initiation time
DEWATERING/EXCAVATION FOR CLOSURE -BY -REMOVAL/ CONVEY MATERIAL
REMOVAL & TREATMENT OF PORE WATER WITHIN ASH IN
MONTHS
88.0
$225,832
$19,873,242
STEP 1: Start dewaterting for Construction time. Based on Construction Time
CLOSURE -BY -REMOVAL AREA
Step 2: Assume CCR material must be stockpiled within impoundment area to
decant prior to loading. Done in conjunction with Step 1. Decant water collected
EXCAVATE ASH FOR CLOSURE -BY -REMOVAL / STOCKPILE ASH
CY
1,016,400
$8.00
$8,131,200
and treated along with pore water from Step 1.
EXCAVATE ASH FROM STOCKPILE / LOAD / HAUL ASH TO
CY
1,016,400
$8.43
$8,568,252
Step 3. Once material has decanted, CCRs must be excavated out of stockpile,
CLOSURE -BY -REMOVAL AREA
loaded on trucks and hauled to close -in -place area
OVER EXCAVATE SOIL FROM CLOSURE -BY -REMOVAL AREA/
CY
203,280
$10.00
$2,032,800
Assume 1 feet of additional material to be removed over total closure by removald
LOAD / HAUL CCR-IMPACTED SOIL TO CLOSE -IN -PLACE AREA
impoundment area.
ASH STABILIZATION BY EXCAVATING AND RECOMPACTING
CY
1,111,111
$16
$17,288,889
Ash stabilization along the stack and sluiced ash perimeter by excavating and
recompacting ash.
EXCAVATE / LOAD / HAUL CCR MATERIAL (OFF -SITE)
CY
0
$57
$0
include if applicable
EXCAVATE / LOAD / HAUL CCR-IMPACTED SOIL (OFF -SITE)
CY
0
$57
$0
include if applicable
DEWATERING / EARTHWORK FOR CLOSE -IN -PLACE
REMOVAL & TREATMENT OF PORE WATER WITHIN ASH
MONTHS
0.0
$225,832
$0
Accounted for in closure by removal time frame.
SPREAD AND COMPACT MATERIAL FROM CLOSURE -BY-
CY
1,219,680
$7.56
$9,220,781
Spread dewatered ash excavated from closure -by -removal area in thin lifts over
REMOVAL AREA
close -in -place area.
ASH REGRADING TO ESTABLISH CROWN
CY
1,671,023
$9.24
$15,440,253
Quantity of earthwory (cut -to -fill) using existing ash to achieve min. 2 % slope prior
to installation of closure system. Quantity calculated using AutoCAD.
RING DRAIN INSTALLATION
L.F.
10,000
$58
$181,215
Linear feet around the close -in -place area
10252018 3 of 7

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Belews Creek
CCR Rule 8 CAMA Compliant
Hybrid Costs
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Pro'ect Costs Sheets
Ash Basin
Hybrid
60432132, 60572391
ACTIVITY :
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6- Hybrid 2013
Kula Kulasingam
10/24/13
Nick Popkowski
BASIS OF THE ESTIMATE
IMF -
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL AREA TO BE RESTORED (AC)
297
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
IMPOUNDMENT AREA TO BE CLOSED -IN -PLACE (AC)
144
IMPOUNDMENTAREA TO BE CLOSED -BY -REMOVAL (AC)
126
EXISTING ASH VOLUME IN AREA TO BE CLOSED -IN -PLACE (CY)
8,959,400
TOTAL ASH VOLUME FROM CLOSURE -BY -REMOVAL (CY)
1,016,400
TOTAL (FINAL) ASH VOLUME TO BE CLOSED -IN -PLACE (CY)
9,975,800
PERIMETER OF CLOSED IN PLACE IMPOUNDMENT (L.F.)
10,000
LENGTH OF CUT -SLOPE AT CLOSE -IN -PLACE / REMOVAL INTERFACE (L.F.)
2,000
HYBRID ESTIMATED COSTS
TASK
ITEM
UNIT
QUANTITY
INSTALLED
UNIT COST
IMPOUNDMENT
CLOSURE COST
NOTES
PERIMETER DITCH /TEMP. DIVERSION BERM GRADING
L.F.
10,000
$12
$120,000
Linear feet around the perimeter of impoundment.
10252018 4 of 7

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Belews Creek
CCR Rule & CAIM1A Compliant
Hybrid Costs
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Pro'ect Costs Sheets
Ash Basin
Hybrid
60432132, 60572391
ACTIVITY :
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6- Hybrid 2013
Kula Kulasingam
10/24/13
Nick Popkowski
BASIS OF THE ESTIMATE
IMF -
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL AREA TO BE RESTORED (AC)
297
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
IMPOUNDMENT AREA TO BE CLOSED -IN -PLACE (AC)
144
IMPOUNDMENTAREA TO BE CLOSED -BY -REMOVAL (AC)
126
EXISTING ASH VOLUME IN AREA TO BE CLOSED -IN -PLACE (CY)
8,959,400
TOTAL ASH VOLUME FROM CLOSURE -BY -REMOVAL (CY)
1,016,400
TOTAL (FINAL) ASH VOLUME TO BE CLOSED -IN -PLACE (CY)
9,975,800
PERIMETER OF CLOSED IN PLACE IMPOUNDMENT (L.F.)
10,000
LENGTH OF CUT -SLOPE AT CLOSE -IN -PLACE / REMOVAL INTERFACE (L.F.)
2,000
::LOSURE SYSTEM
CONSTRUCTION
STORMWATER
MANAGEMENT/
E&S CONTROLS /
SITE
RESTORATION
CONTINGENCY/
ENGINEERING
SUPPORT
POST -CLOSURE
HYBRID ESTIMATED COSTS
TASK
ITEM
UNIT
QUANTITY
INSTALLED
UNIT COST
IMPOUNDMENT
CLOSURE COST
NOTES
CLOSURE SYSTEM CONSTRUCTION
18" PROTECTIVE COVER SOIL
CY
348,480
$13
$4,530,240
18 inches of common soil placed over closure by removal area (obtained off -site)
6" TOPSOIL
CY
116,160
$13
$1,510,080
6 inches of topsoil (obtained offsite) placed over closure by removal area.
COMPACTED LOW PERM. SOILS (Kv<1x1015 cm/sec)
CY
0
$15
$0
not used.
FLEXIBLE MEMBRANE LINER (FML)
SQ. FT.
6,899,904
$0.42
$2,911,759
Flexible membrane liner placed over close -in -place area. Assume quantity needed
is 10 %more than close -in -place area.
GEOCOMPOSITE DRAINAGE LAYER
SQ. FT.
6,899,904
$0.60
$4,139,942
Geocomposite drainage layer placed over close -in -place area. Assume quantity
needed is 10 % more than close -in -place area.
GEOSYNTHETIC CLAY LINER (GCL)
SQ. FT.
0
$0.72
$0
not used.
STORMWATER MANAGEMENT/ E&S CONTROLS / SITE RESTORATION
PERMANENT RIPRAP STORMWATER CHANNELS
Tons
7,250
$50
$362,500
Assume 10,000 If x 10 ft widex 1 ft thick, 145 pcf riprap lined stormwater channels.
SITE EROSION AND SEDIMENT CONTROL
ACRE
297
$2,000
$594,000
Assume total area to be restored will require site erosion and sediment control.
BACKFILL AND REGRADING OF CLOSURE -BY -REMOVAL AREA
CY
407,400
$3.50
$1,425,900
Assume 2 feet of additional soil material (obtained onsite) graded over total closure -
by -removal area.
TOPSOIL
CY
101,850
$13
$1,324,050
Assume 6-inches of top soil needed (obtained offsite) to establish vegetative
stabilization over total closure -by -removal area.
SEED / FERTILIZE / MULCH
ACRE
297
$3,767
$1,118,725
Assume total area of disturbance will be mulched, fertilized, and seeded.
CONTINGENCY/ ENGINEERING SUPPORT
1
CONTINGENCY(25%)
LS
1
$26,147,274
$26,147,274
2
ENGINEERING SUPPORT (DESIGN AND CQA)
LS
1
$4,500,000
$4,500,000
POST -CLOSURE
GROUNDWATER MONITORING
ANNUAL
30
$480,833
$14,424,990
Annual groundwater monitoring costsfor each CCR impoundment are based on current
groundwater monitoring system
10252018 5 of 7

PROJECT:
PLANT NAME:
CLOSURE TYPE:
SHEET:
REV. NO.:
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Belews Creek
CCR Rule & CAIM1A Compliant
Hybrid Costs
B
SUBJECT:
IMPOUNDMENTNAME:
CLOSURE METHOD:
AECOM JOB NO.:
CALCULATION SHEET
Preliminary Pro'ect Costs Sheets
Ash Basin
Hybrid
60432132, 60572391
ACTIVITY :
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6- Hybrid 2013
Kula Kulasingam
10/24/13
Nick Popkowski
BASIS OF THE ESTIMATE
IMF -
YEAR COST BASIS
2018
AREA OF OPEN FREE WATER IN IMPOUNDMENT (AC)
Not Used
TOTAL IMPOUNDMENT AREA (AC)
270
AVG. DEPTH OF FREE WATER (FT)
Not Used
TOTAL AREA TO BE RESTORED (AC)
297
VOLUME OF FREE WATER IN IMPOUNDMENT (GAL)
Not Used
IMPOUNDMENT AREA TO BE CLOSED -IN -PLACE (AC)
144
IMPOUNDMENTAREA TO BE CLOSED -BY -REMOVAL (AC)
126
EXISTING ASH VOLUME IN AREA TO BE CLOSED -IN -PLACE (CY)
8,959,400
TOTAL ASH VOLUME FROM CLOSURE -BY -REMOVAL (CY)
1,016,400
TOTAL (FINAL) ASH VOLUME TO BE CLOSED -IN -PLACE (CY)
9,975,800
PERIMETER OF CLOSED IN PLACE IMPOUNDMENT (L.F.)
10,000
LENGTH OF CUT -SLOPE AT CLOSE -IN -PLACE / REMOVAL INTERFACE (L.F.)
2,000
CONTINGENCY/
ENGINEERING
COST
HYBRID ESTIMATED COSTS
TASK
ITEM
UNIT
QUANTITY
INSTALLED
UNIT COST
IMPOUNDMENT
CLOSURE COST
NOTES
OPERATIONS & MAINTENANCE (O&M)
ANNUAL
30
$500,515
$15,015,456
Annual O&M costs are 3475.80/ac/yr for closed area with cap. Based on Q3 2018 Post
Closure Maintenance data.
CONTINGENCY/ ENGINEERING COST
1
CONTINGENCY(25%)
LS
1
$7,360,112
$7,360,112
2
ENGINEERING COST(10%)
LS
1
$3,680,056
$3,680,056
TOTAL
$175,716,985
Preliminary based on information available as of 10/24/2018
10252018 6 of 7

PROJECT
PLANT NAME:
CLOSURE TYPE:
SHEET
REV. NO.
AXOM
CCR IMPOUNDMENT CLOSURE ESTIMATES FOR DUKE ENERGY
Bel —Creek
CCR Rule & CAMA Compliant
Hybrid Assumptions
B
SUBJECT
IMPOUNDMENT NAME:
CLOSURE METHOD:
CLOSUREYEAR:
AECOM JOB NO.
�'■
CALCULATION SHEET
Preliminary Promect Costs Sheets
Ash Basin
Hybrid
0
60432132,60572891
ACTIVITY
CLOSURE OPTION:
LAST UPDATED BY:
DATE LAST MODIFIED:
REVIEWED BY:
Cost Summary: Hybrid 2018 Cost Estimate for CCR Impoundment
Option 6-Hybrid 2018
Kula Kulasingam
10/24/18
Nick Popko—ki
KEY ASSUMPTIONS
The following key assumptions and limitations are associated with the project design, implementation and performance:
1
The cost estimates were prepared using 2018 dollars and do not include any escalation.
2
A 25% contingency has been included for this cost estimate.
3
Engineering design and CQA cost has been included for this cost estimate based on reasonable assumptions.
4
The unit rate costs are based on data provided by Duke Energy. If no data is available, AECOM supplemented with rates from our experience.
5
Free water removal and treatment was assumed to continue throughout the project initiation period.
6
Interstitial water treatment was assumed to continue until construction is completed.
7
Ash to be moisture conditioned and compacted in the stack area.
8
Removal of existing structures/piping includes the excavation and disposal of existing structures within the limits of waste and the bulkheading or grouting of existing outlet pipes that extend beyond the limits of
waste. This will be performed during the closure -by -removal of an impoundment.
9
AECOM has assumed all CCR material excavated must be stockpiled in close proximity to the impoundment to be decanted. After decanting, the material will be excavated, loaded, and hauled to an on -site
impoundment to be closed -in -place.
10
AECOM has assumed all material excavated from areas to be closed by removal will be used for crown construction/soil regrading for closed -in -place areas.
11
AECOM has assumed an over -excavation of 1 foot is necessary to achieve closure -by -removal conditions.
12
Cap cross section for the CCR impoundment will consist of flexible membrane liner, geocomposite drianage layer, and 18-inches of protective cover soil (Kv<1x10-5 cm/sec) overlain by 6-inches of topsoil.
13
Common soil for embankment and protective cover soil construction are available onsite and topsoil would come from offsite
14
AECOM has assumed groundwater monitoring costs are for the existing network system. Groundwater monitoring costs do not include costs incurred for any additional well installation. Maintenance costs for
wells are included in post -closure O&M costs.
15
O&M costs include, but are not limited to, the maintenance/repair of the groundwater monitoring system and general maintenance of the former CCR impoundment area.
16
Statements of Probable Construction Cost prepared by URS represent URS's judgment as a design professional familiar with the construction industry. It is recognized, however, that neither AECOM nor the
Owner has control over the cost of labor, materials or equipment nor over the contractor's methods of determining the bid price or other competitive bidding, market, or negotiating conditions. Accordingly,
AECOM cannot and does not warrant or represent that proposals, bids or actual construction costs will not vary from any statement of Probable Construction Cost or other estimates or evaluations prepared by
AECOM.
Preliminary based on information available as of 10/24/2018
1
10/25/2018 7 of 7

Attachment C

Revision H
Preliminary Scoring for Evaluation of Closure Options
Closure Options Evaluation Worksheet
Ash Basin Closure - Master Programmatic Document
Duke Energy
Zero (0) values have been entered in "Calculated or User Selected
Site Name: BeleWs Creek Plant = Option -Specific User Input Score" under Beneficial Reuse to prevent division by zero error
Date: 10/25/18 "Mi = Calculated Value text in calculated score cells.
Threshold Criteria: All closure options must comply with the following threshold criteria based on Duke Energy Guiding Principles for
Ash Basin Closure
1. Provide continued geotechnical stability meeting appropriate safety factors under applicable loading conditions
2. Provide flow capacity and erosion resistance during design storm and flooding conditions
3. Effectively mitigate groundwater impacts (in conjunction with GW remediation where present)
4. Comply with applicable state and federal regulations (e.g. North Carolina Coal Ash Management Act)
Option
Description
1
Option 1-
Closure in Place
2
Option 2
- Hybrid 2016 Closure Option - Reduced Closure Footprint Within the Ash Basin
3
Option 3
- Removal: Onsite Landfill Inside the Excavated Ash Basin
4
Option 4
- Removal: Onsite Landfill Outside the Ash Basin
5
1 Option 5
- Removal: Offsite Landfill
6
10ption 6
- Hybrid 2018 Closure Option - Reduced Closure Footprint Within the Ash Basin
Not carried through for further consideration.
Environmental Protection and Impacts
Weight:
30%
Refer to
Modeled plume intersecting surface water
Please refer to the Groundwater Sub -Scoring Document for details
Pr
GW Sub -Scoring Sheet
24%
7.1%
Modeled groundwater impact beyond the current
Refer to
Please refer to the Groundwater Sub -Scoring Document for details
compliance boundary
GW Sub -Scoring Sheet
24%
7.1%
Refer to
Modeled off -site groundwater impact
Please refer to the Groundwater Sub -Scoring Document for details
GW Sub -Scoring Sheet
24%
7.1%
Relative rank based on visual interpretation of
Refer to
Please refer to the Groundwater Sub Scoring Document for details
modeled boron plume
GW Sub -Scoring Sheet
14%
4.1°
Air emissions off -site (based on miles driven round-
Interpolation. Min value
trip)
scores 10. Max value scores 0.
Truck miles driven
Miles
0
0
10
10
10
5%
1.5°
Air emissions on -site cubic yards of
Interpolation. Min value
Volume of material
excavation/movement
scores 10. Max value scores 0.
excavation/movemen
t
Cu.Yds
111 111 1 111 off .11 111 2,000,000
10,000,000
10
0
9
5%
1.5%
Interpolation. Min valueDisturbed
Avoidance of greenfield disturbance
acres of
scores 10. Max value scores 0.
greenfield
Acres
1 1 1 30
130
8
0
10
5%
1.5%
1.99
2.13
2.21
Cost
Weight:
35%
Closure Cost
Interpolation. Min value
scores 10. Max value scores 0.
Closure Cost
USD
111 111 : 111 111 111 111 $ 134,000,000.00 $
478,000,000.00
9.7
0.0
10.0
80%
28.0%
Operation, Maintenance and Monitoring Cost
OM&M Cost
USD
111 111 111 111 1 111 111 $ 32,000,000.00 $
59,000,000.00
0.0
10.0
7.0
20%
7.0%
2.72
0.70
3.29
Schedule
Weight:
15%
•.
•.
•.
•.
Time to move first
Initiation Time
Interpolation. Min value
scores 10. Max value scores 0.
ash
Months
1 30
54
10
0
8
30%
4.5%
Construction Duration
Estimated durations
Months r
1
76
138
10
0
8
70%
10.5%
1.50
0.00
3.20

Revision H
Preliminary Scoring for Evaluation of Closure Options
Closure Options Evaluation Worksheet
Ash Basin Closure - Master Programmatic Document
Duke Energy
Zero (0) values have been entered in "Calculated or User Selected
Site Name: BeleWs Creek Plant = Option -Specific User Input Score" under Beneficial Reuse to prevent division by zero error
Date: 10/25/18 10 �1= Calculated Value text in calculated score cells.
Regional Factors
Weight:
15%
Plan or potential for beneficial reuse of site
Subjective
Not Used For Subjective Scoring
•
•
•
5%°
0.8%
Interpolation. Min value
Imported soil needs
scores 10. Max value scores 0.
Soil Imported
CY
115000
350000
6
0
10
5%
0.8%
Interpolation. Maxvalue
scores 10. Zero value scores 0.
Beneficial reuse of CCR
Fraction Used
None •
• •
0
0
0
0
0
15%
2.3%
Interpolation. Min value
scores 10. Max value scores 0.
Transportation impact (based on miles driven)
Miles Driven
Miles •
•
0
1
10
0
10
65%
9.8%
Subjective 0 to 10: 10 is the
Noise impact due to on -site activity (based on
least noise;
*
proximity of neighbors to on -site work areas)
0 is the most noise.
•
5%
0.8%
Not Used For Subjective Scoring
Subjective 0 to 10; 10 is the
View impact (based on final height of storage facility
least visual;
and land uses within viewshed)
0 is the most visual.
•
•
5%
0.7%
1.17
0.03
1.16
Constructability
Weight:
5%
Subjective 0 to 10: 10 is the
Consider stormwater management, geotechnical,
least co m m pl icated;
Not Used For Subjective Scoring
and dewatering
0 is the most complicated
•
100%
5.0%
0.50
0.30
0.30
•. •
7.88
3.16
8.16

Revision H
Criteria for Evaluation of Closure Options
Closure Options Evaluation Worksheet
Ash Basin Closure - Master Programmatic Document
Duke Energy
Threshold Criteria: All closure options must comply with the following threshold criteria based on Duke Energy Guiding
Principles for Ash Basin Closure
1. Provide continued geotechnical stability under applicable loading conditions and safety factors
2. Provide flow capacity and erosion resistance during design storm and flooding conditions
3. Effectively mitigate groundwater impacts
4. Comply with applicable state and federal regulations (e.g. North Carolina Coal Ash Management Act)
Category
Criterion
Guidance
Modeled plume intersecting surface water
Please refer to the Groundwater Sub -Scoring Document for details
Modeled groundwater impact beyond the current compliance boundary
Please refer to the Groundwater Sub -Scoring Document for details
Modeled off -site groundwater impact
Please refer to the Groundwater Sub -Scoring Document for details
Relative rank based on visual interpretation of modeled boron plume
Please refer to the Groundwater Sub -Scoring Document for details
Air emissions off -site (based on miles driven round-trip)
Based on truck miles driven for hauling CCR and soil.
Air emissions on -site cubic yards of excavation/movement
Based on total cubic yards of cut and fill on site as a surrogate for gallons of fuel
consumed.
Avoidance of greenfield disturbance
Refer to Scoring System and Required Input columns on scoring sheet.
•
Capital Cost
From rough order -of -magnitude cost estimate or detailed cost estimate.
Operation, Maintenance and Monitoring Cost
Initiation Time
From preliminary schedule for designing, permitting, bidding and constructing the
option.
Construction Duration
Plan or potential for beneficial reuse of site
Refer to Scoring System and Required Input columns on scoring sheet.
Imported soil needs
Refer to Scoring System and Required Input columns on scoring sheet.
Beneficial reuse of CCR
Refer to Scoring System and Required Input columns on scoring sheet.
Transportation impact
Based on truck miles driven for hauling CCR and soil.
Noise impact due to on -site activity
Based on proximity of neighbors to specific on -site work areas.
View impact
Based on final height of storage facility and land uses within viewshed.
•
Consider stormwater management, geotechnical, and dewatering
Subjective and relative comparison to other options

Environmental Groundwater Sub -scoring Worksheet
Closure Options Evaluation
Duke Energy
•
• • •
•
Station/Plant Name: Belews Creek Steam Station
Evaluation Criteria:
Criteria 1. Modeled Plume Intersecting Surface Water
Score
Modeled plume' does not intersect surface waters after 10 years
10
Modeled plume' does not intersect surface waters after 100 years
5
Modeled plume' does not intersect surface waters after 200 years
0
(Option 1)
(Option 4)
(Option 6)
Closure By Removal: Onsite Landfill Outside
Closure In Place
Hybrid 2018 Closure Option
the Ash Basin
Criteria 1 Score
10
10
10
Criteria 2. Groundwater Impact Beyond the current z Compliance Boundary
Score
Modeled plume' is within current compliance boundary after 10 years
10
Modeled plume' is within current compliance boundary after 100 years
5
Modeled plume' is within current compliance boundary after 200 years
0
(Option 1)
(Option 4)
(Option 6)
Closure By Removal: Onsite Landfill Outside
Closure In Place
Hybrid 2018 Closure Option
the Ash Basin
Criteria 2 Score
6
6
6
Criteria 3. Modeled Off -site Impact
Score
Modeled plume' does not go off -site
10
Modeled plume' is predicted to remain off -site after 100 years
5
Modeled plume' is predicted to remain off -site after 200 years
0
(Option 1)
(Option 4)
(Option 6)
Closure By Removal: Onsite Landfill Outside
Closure In Place
Hybrid 2018 Closure Option
the Ash Basin
Criteria 3 Score
6
6
6
Criteria 4. Relative rank based on visual interpretation of modeled boron plume
Score
Ranked #1 among the three Closure Options based on visual interpretation of modeled boron plume
10
Ranked #2 among the three Closure Options based on visual interpretation of modeled boron plume
5
Ranked #3 among the three Closure Options based on visual interpretation of modeled boron plume
0
(Option 1)
(Option 4)
(Option 6)
Closure By Removal: Onsite Landfill Outside
Closure In Place
Hybrid 2018 Closure Option
the Ash Basin
Criteria 4 Score
0
10
5

Environmental Groundwater Sub -scoring Worksheet
Closure Options Evaluation
Duke Energy
Ash Basin Groundwater Sub
-Scoring Document Justification
Belews Creek
A Ad
(Option 6)
(Option 1)
(Option 4)
Closure By Removal: Onsite Landfill Outside
Justification Notes
Closure In Place
Hybrid 2018 Closure Option
the Ash Basin
Criteria 1. Modeled Plume Intersectinq Surface
Based on the predictive model for the year 2050, found in the
Based on the predictive model for the year 2050, found in the
Based on the predictive model for the year 2050, found in the
Water
October 2018 Revised Groundwater Flow and Transport
October 2018 Revised Groundwater Flow and Transport
October 2018 Revised Groundwater Flow and Transport
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
boron concentrations for the final cover scenario with natural
boron concentrations for the hybrid scenario with natural
boron concentrations for the excavation scenario with natural
attenuation and existing extraction wells did not show boron of
attenuation and existing extraction wells did not show boron of
attenuation and existing extraction wells did not show boron of
4,000 ppb or greater intercepting a surface water body based on
4,000 ppb or greater intercepting a surface water body based on
4,000 ppb or greater intercepting a surface water body based on
current permit status.
current permit status.
current permit status.
Criteria 2. Groundwater Impact Beyond the
1 6
6
6
Current Compliance Boundary
Based on the predictive model for the year 2050 and 2100, found
Based on the predictive model for the year 2050 and 2100, found
Based on the predictive model for the year 2050 and 2100, found
in the October 2018 Revised Groundwater Flow and Transport
in the October 2018 Revised Groundwater Flow and Transport
in the October 2018 Revised Groundwater Flow and Transport
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
boron concentrations for the final cover scenario with natural
boron concentrations for the hybrid scenario with natural
boron concentrations for the extraction scenario with natural
attenuation and existing extraction wells showed boron of 4,000
attenuation and existing extraction wells showed boron of 4,000
attenuation and existing extraction wells showed boron of 4,000
ppb or greater outside of the current compliance boundary in
ppb or greater outside of the current compliance boundary in
ppb or greater outside of the current compliance boundary in
2050 and within the compliance boundary by 2100. Based on
2050 and within the compliance boundary by 2100. Based on
2050 and within the compliance boundary by 2100. Based on
professional judgement, a score of 6 was determined to be most
professional judgement, a score of 6 was determined to be most
professional judgement, a score of 6 was determined to be most
appropriate.
appropriate.
appropriate.
Criteria 3. Modeled Off -site Impact
6
6
6
Based on the predictive model for the year 2050 and 2100, found
Based on the predictive model for the year 2050 and 2100, found
Based on the predictive model for the year 2050 and 2100, found
in the October 2018 Revised Groundwater Flow and Transport
in the October 2018 Revised Groundwater Flow and Transport
in the October 2018 Revised Groundwater Flow and Transport
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
Modeling Report for Belews Creek Steam Station, simulated
boron concentrations for the final cover scenario with natural
boron concentrations for the hybrid scenario with natural
boron concentrations for the excavation scenario with natural
attenuation and existing extraction wells showed boron of 4,000
attenuation and existing extraction wells showed boron of 4,000
attenuation and existing extraction wells showed boron of 4,000
ppb or greater outside of the current Duke Energy property
ppb or greater outside of the current Duke Energy property
ppb or greater outside of the current Duke Energy property
boundary in 2050 and within the compliance boundary by 2100.
boundary in 2050 and within the compliance boundary by 2100.
boundary in 2050 and within the compliance boundary by 2100.
Based on professional judgement, a score of 6 was determined to
Based on professional judgement, a score of 6 was determined to
Based on professional judgement, a score of 6 was determined to
be most appropriate.
be most appropriate.
be most appropriate.
Criteria 4. Relative rank based on visual
interpretation of modeled boron plume
Based on a review of boron concentrations found in the October
Based on a review of boron concentrations found in the October
Based on a review of boron concentrations found in the October
2018 Revised Groundwater Flow and Transport Modeling Report,
2018 Revised Groundwater Flow and Transport Modeling Report,
2018 Revised Groundwater Flow and Transport Modeling Report,
this scenario is not marginally better than Option 4 Closure in
this scenario is marginally better than Option 1 Closure In Place
this scenario is marginally better than Option 1 Closure In Place.
Place or Options 6 Hybrid Closure.
and Option 6 Hybrid Closure.
Notes:
1. Based on avaliable data at the time of scoring, the modeled plume considered boron at a concentration of 4,000 ug/I or greater; 4,000 µg/L does not represent a remediation goal, however this
concentration does represent the EPA Tap Water Regional Screening Level (RSL) in resident tapwater for boron.
2. The current compliance boundary is the compliance boundary found in the figure "Waste and Compliance Boundaries" provided to NCDEQ on 2/15/18.