FERCrequest_20061005

PhDuke
Energy®
October 5, 2006
Darlene Kucken
North Carolina Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Catawba-Wateree Hydroelectric Project (FERC No. 2232)
Bridgewater Powerhouse Replacement
Dear Darlene:
Duke Energy Lake Services
EC12Q / PO Box 1006
Charlotte, NC 28201-1006
Duke Power Company LLC, doing business as Duke Energy Carolinas, LLC (Duke) is soliciting
your feedback and support on proceeding to request FERC approval to construct the Bridgewater
Hydro Powerhouse replacement at the Linville Dam.
Duke is currently undertaking the stabilization of the dams at the Bridgewater Development.
Stabilization of the Linville Dam requires the removal of the current Bridgewater Powerhouse
before dam stabilization work can begin. Replacement of the existing Bridgewater Powerhouse
with a new powerhouse or valve system designed to meet relicensing requirements has been
discussed regularly during the past three years with the relicensing process participants and is
reflected in Paragraph 4.4 of the Comprehensive Relicensing Agreement filed with the Federal
Energy Regulatory Commission (FERC) on August 29, 2006.
Of course, constructing a new powerhouse or valve system requires FERC approval. There are
two approval options, either approval as part of the New License for the Catawba-Wateree
Project or more immediate approval as part of the current dam stability project (pursuant to 18
CFR Part 12 [Safety of Water Power Projects and Project Works]).
Duke believes that proceeding with the replacement of the Bridgewater Powerhouse with a new
powerhouse or valve system as soon as possible presents two primary advantages. First,
proceeding with the stabilization effort allows Duke to fulfill important FERC dam stability
requirements on schedule. Second, approving the replacement under 18 CFR Part 12 regulations
positions Duke to construct the powerhouse replacement sooner and without the risk of delaying
construction until after the issuance of the New License by the FERC.
Please provide your feedback to me by October 31, 2006. A statement of your level of support
for FERC approval under 18 CFR Part 12 regulations to build the Bridgewater Powerhouse
replacement will be an important consideration for the FERC as it evaluates Duke's request. The
enclosed Project Information Document provides you with more detailed information. Also, an
on -site meeting at the Bridgewater Development is planned for October 24, 2006 that will
include a discussion of the powerhouse replacement. Should you have any questions or would
like more information regarding this matter I will be happy to discuss with you further. You may
contact me at 704-382-5778 or [e-mail].
www.duke-energy com

Sincerel
E. Mark Oakley, PE
Catawba-Wateree Relicensing oject Manager

Catawba-Wateree Project (FERC No. 2232)
Bridgewater Development:
Potential New Powerhouse
Project Information Document
October 2, 2006

Section 1 — Introduction & Purpose
This document provides a description of a new powerhouse structure currently being
considered for the Bridgewater Development of the Catawba-Wateree Project (FERC
#2232). The existing powerhouse is to be demolished as part of the seismic dam safety
remediation project (ESSI Project) at the Linville Dam. The existing powerhouse is
located at the downstream toe of the Linville Dam. The potential new powerhouse would
be located downstream of the existing powerhouse, outside of the footprint of the dam
remediation project. Water flow to the new powerhouse from Lake lames would be via
an extension of the existing water conveyance system. An alternative means of releasing
flows, via a system of large valves located in a structure at the same location, is also
technically viable and would be implemented in the event that the new powerhouse is
proven not to be feasible.
Removal and replacement of the existing powerhouse is an integral component of the
seismic dam safety project and is a critical path scheduling activity for that important
project. The new powerhouse would be capable of meeting flow release requirements that
have been negotiated with stakeholders as part of the relicensing of the Catawba-Wateree
Project. The new powerhouse implementation plan as described in this document will
minimize interruption to downstream aquatic habitat, recreation and water supply needs.
This is discussed in detail in Section 5 of this document.
Duke Energy's objective is to complete the Linville Dam Seismic Project in accordance
with the schedule that has been submitted to the FERC — Division of Dam Safety and
Inspection. Replacement of the Bridgewater Powerhouse has been determined to be the
most cost effective and risk -averse option for the execution for the dam safety
remediation. Accordingly, Duke considers the powerhouse replacement to be a
component of the dam safety project that must be completed as scheduled in order to
complete all dam safety activities as scheduled.
Revised: October 2, 2006

Section 2 — Project Bacbground / History
The reservoir for the Bridgewater Development, Lake James, is formed by three large
earth dams, Paddy Creek Dam, Catawba Dam and Linville Dam. The Bridgewater
Powerhouse is located immediately downstream of the Linville Dam. All three
embankments were constructed using a method termed semi -hydraulic fill. The upstream
and downstream portions of the dams were placed by loose dumping from side dump rail
cars. Trestles supporting the rails were left in place. The central portions of the
embankments were completed by hydraulically sluicing soils from the dumped upstream
and downstream zones. No other compactive effort was utilized. While the resulting
embankments have performed well since their completion in 1918, portions of the
embankment materials are susceptible to strength loss during the design seismic event.
This design event is significantly larger than any earthquake activity that has been
experienced at the project site in recorded history.
A series of investigations and analyses beginning in the I980's have concluded that
remediation of all three dams is necessary. Work began on the strengthening of Paddy
Creek Dam in 2005. Analyses of the Linville Dam confirm the need for remediation of
that structure. Several options were evaluated to accomplish the remediation. The
selected option involves construction of a compacted earthfill stability berm on the
downstream portion of the Linville Dam. Construction of this berm will require that the
existing powerhouse be demolished and an alternative means of releasing flows from
Revised. October 2. 2006

Section 2 — Project Background 1 History
Lake James be constructed outside the footprint of the berm. To accomplish this, Duke
Energy is considering building a new powerhouse downstream of the current
powerhouse. This option was reviewed by an independent Board of Consultants (Board)
and FERC representatives at a meeting held on February 11, 2005. The Board agreed
with the option to remove the existing powerhouse, recognizing that the removal of the
powerhouse is an integral component of the Linville Dam remediation schedule. The
Board issued a letter report dated February 25, 2005 which was submitted to the FERC
April 14, 2005.
The planning and initial design work for the remediation project, including the
demolition of the existing powerhouse and construction of a new powerhouse or valve
structure is in progress. A description of the potential powerhouse is provided in Section
3 and the schedule showing the powerhouse development as part of the dam remediation
critical path is provided in Section 4. Final development and implementation of the
powerhouse is dependent on confirmation of estimated costs. An alternative means of
releasing flows, a system of large valves, is also technically viable and would be
implemented in the event that the new powerhouse is proven not to be feasible.
4 Revised: October 2, 2006

Section 3 — Project Description
Note: Duke Energy's intent at this time is to replace the current powerhouse with a new
powerhouse with generating equipment. The implementation of the new powerhouse at
Linville Dam is dependent an a final business case confirmation by Duke Energy. In the
event the new powerhouse is not the selected alternative, a system of large valves would
be installed to provide the needed capability to meetflow and water quality requirements
at this location. In this case also, the valve system will be required in order to meet the
ESSI schedule for the Linville Dam.
The potential new powerhouse will be constructed approximately 200 feet downstream of
the existing Bridgewater Powerhouse. An aerial photograph with the new powerhouse
concept superimposed is provided in Section 6. A new length of steel penstock will be
constructed to connect the existing water conveyance to the new powerhouse. Hydraulic
transient analysis has confirmed that the existing water conveyance components will
support the new unit requirements without the need for surge or pressure relief devices.
No modification to the existing intake will be required. The existing powerhouse will
remain operational while the new powerhouse is being constructed. The outage time
required to connect and begin operating the new powerhouse after the existing
powerhouse is taken out of service will be minimized.
The new powerhouse will be a reinforced concrete structure housing three vertical shaft
Francis type turbine generating units. There will be two main generating units and one
auxiliary unit sized to supply continuous minimum flow downstream. Each unit will have
an isolation valve. The generating units are sized and configured so that they can be run
individually or in combinations to support the requirements for continuous minimum
flow and recreation flow in the Bridgewater tailrace as defined in the Comprehensive
Relicensing Agreement for the Catawba-Wateree Hydro Project (see Section 5). In
addition, the units will be capable of providing flow aeration to enhance dissolved
oxygen levels in the tailrace. The units will release water into a short tailrace channel
which leads to the Catawba River. Provisions will be made to protect against erosion of
the river's east bank. The existing switchyard will be modified to accommodate the
seismic remediation geometry and the new powerhouse electrical requirements. The
powerhouse will be designed for remote operation from Duke's Hydro Central operations
center in Charlotte, N.C.
The powerhouse will be a low profile configuration with no machine hall and with the
generating units fully enclosed. A traveling gantry crane to support unit assembly and
disassembly will be visible on the deck of the powerhouse. This is similar to Duke
Energy's Cowans Ford and Jocassee powerhouse configurations. Approximate
dimensions will be 114 feet long, 75 feet wide with 36 feet above ground height.
Preliminary drawings of the powerhouse layout are provided as attachments to this
document in Section 6. The table below provides a comparison of the existing and new
powerhouse. Information for the new powerhouse represents design basis assumptions
and could be revised as equipment selection is finalized.
Revised: October 2. 2006

Section 3 — Project Description
Table 3-1 Powerhouse Comparison
Parameter
Existing Powerhouse
New Powerhouse
Number of Units
2
3
Turbine Type
Francis — Vertical
Francis — Vertical
Generator Type
AC Synchronous
AC, Synchronous
Installed Capacity
18.0 MW
26.4 MW
Station Flow at Peak Efficiency
2,228 cfs
2,645 cfs
Maximum Hydraulic Capacity
2,946 cfs
3,260 cfs
Unit Flow Rate
1,114 cfs
1,250 cfs
Unit Flow Min. Flow Unit
NA
145 cfs
Maximum Generator Output
20,000 kW
34,500 kW
Turbine Runner Diameter
94 inches
Main — 103 inches
Min. Flow — 40 inches
Per 18CFR§11.1(i)
Revised: October 2, 2006

Section 4 — Schedule
The schedule for the design, construction and commercial operation of the new
powerhouse structure at the Bridgewater Development is linked to the schedule for the
seismic dam safety remediation (ESSI Project) of the Linville Dam. The new
powerhouse must be completed and fully operational prior to the initiation of the
dam remediation at Linville Dam. ESSI construction is scheduled to begin in July,
2010. Engineering, permitting and licensing activities are all critical path for the
powerhouse project and therefore critical path for the seismic project as well. This
schedule has been filed with the FERC's Division of Dam Safety and Inspection.
A preliminary milestone schedule has been developed that supports the critical path
requirements of the ESSI project. This schedule is shown below. As noted, preliminary
engineering is in progress and the request for proposal to supply major equipment has
been issued to Original Equipment Manufacturers. These ongoing activities are
mandatory to assure that the ESSI Project schedule can be achieved.
TASK
Start
Finish
Powerhouse Evaluation & Design
Wed 8117/06
Mon 8/25/08
Task 1 Advance Conceptual Design
Wed 8117/05
Wed 2/15/06
Task 2 Major Equipment Vendor
Selection
Wed 10/26/05
Thu 10/12/06
Specification Preparation
Wed 10/26/05
Thu 5/25106
Bid & Award Equip Vendor
Fri 6/23/06
Thu 10/12/06
Release E/M Vendor Engineering
Thu 10/12/06
Thu 10/12/06
E/M Vendor Engineering
Fri 10/13/06
Thu 3/29/07
Review Vendor & Prepare 30%
Design Package
Fri 10/20/06
Fri 4/27/07
Submit Package to FERC
Fri 4/27/07
Fri 4/27/07
FERC Reviews Package
Mon 4/30/07
Fri 7/27/07
FERC Approves Design
Fri 7/27107
Fri 7127/07
Task 3 EPC Specification
Preparation
Mon 3112/07
Mon 8/27/07
Task 4 EPC Bid & Award
Mon 8/27/07 •
Mon 12/17/07
EPC Powerhouse Design
Mon 12/17/07
Mon 8125/08
Release Vendor Manufacture
Mon 12/17/07
Mon 12/17/07
Vendor Manufacturing
Mon 12/17/07
Mon 319/09
Licensing Considerations
Sianing of Final Agreement
Thu 7120/06
Fri 8/11/06
Consult with signatories to Final
Agreement
Fri 9/1/06
Fri 10/13/06
Submit consultation record to the
FERC
Tue 10/31/06
Tue 10/31/06
Powerhouse Construction & Startup
Mon 417108
Tue 1/24/12
Powerhouse Construction
Mon 4/7/08
Mon 4/5/10
Tie Into Existing Penstock
Mon 318/10
Mon 4/5/10
Tie Into Modified Switchyard
Mon 1/11110
Mon 513110
Check-out & Start-up
Mon 4/5/10
Mon 5/31/10
Powerhouse Commissioning
Complete
Mon 5/31/10
Mon 5/31/10
Demolition of Existing Powerhouse
Mon 5/31/10
Mon 1111/10
ESSI Construction & Closeout
Wed 7114/10
Tue 1/24/12
7 Revised: October 2, 2006

Section 5 — Licensing Considerations
The Bridgewater Development is one of eleven developments comprising the Catawba-
Wateree Hydroelectric Project. The Existing License expires in August 2008; the
application for a New License was filed with the FERC on August 29, 2006.
Duke has been preparing the license application for more than three years by conducting
numerous technical studies as well as negotiating with more than 80 different entities to
reach an agreement regarding continued operation of the Project.
This agreement, known as the Comprehensive Relicensing Agreement (Agreement)
became effective on August 12, 2006, and has been filed with the Commission
concurrent with the submittal of the Application for New License on August 29, 2006.
Participants in the Agreement include the North Carolina Division of Water Resources,
the North Carolina Division of Water Quality, the North Carolina Wildlife Resources
Commission, the North Carolina Wildlife Federation, McDowell County, Trout
Unlimited, Burke County, the City of Morganton (which owns and operates a drinking
water intake several miles downstream of the potential new powerhouse), and many
others.
There are three regulatory options for moving forward with the construction of a new
powerhouse at the Bridgewater Development.
1. The Licensee requests an amendment of the Existing License. This would require
the FERC to process both the Application for a New License and the license
amendment request concurrent with each other. Given the amount of time to
process such requests, it does not appear likely that a license amendment would
be issued in time to allow the ESSI project to proceed without delays.
2. The Licensee incorporates a new powerhouse into its pending Application for a
New License. While this option eliminates the FERC having to process two
requests concurrently, the timing of issuing a New License is inconsistent with the
ESSI schedule.
3. The FERC orders the Licensee to construct a powerhouse pursuant to 18 CFR
Part 12 [Safety of Water Power Projects and Project Works]. Of the three
options, this provides the most efficient avenue for proceeding with construction
of the powerhouse in a manner that supports the existing ESSI project.
The replacement of the Bridgewater Powerhouse was discussed during relicensing
stakeholder team meetings. All participants were advised in advance that the existing
Bridgewater Powerhouse would be removed and replaced with either new generating
units or a system of flow release valves and that either replacement structure would be
designed to meet all flow release and water quality requirements included in the
Agreement. Stakeholder negotiations were not constrained by current powerhouse
performance criteria. The units proposed for the new powerhouse are being designed to
deliver the flows and meet the water quality conditions set forth in the Agreement.
8 Revised: October 2, 2006

Section 5 — Licensing Considerations
Proceeding with construction of the powerhouse as quickly and as efficiently as possible
should be viewed as a positive by Parties to the Agreement. These Parties have already
devoted three years to evaluating all aspects associated with continued operation of the
Catawba-Wateree Project. While Duke Energy acknowledges that construction of the
replacement powerhouse does not exempt the Bridgewater Development from
comprehensive development considerations that FERC must address during the
relicensing process, it is doubtful that any issues associated with construction of a new
powerhouse have not already been exhaustively examined, discussed, and resolved.
Proceeding with requiring construction of a new powerhouse in concert with the ESSI
project (i.e., beginning in early 2008) will enable the construction to occur earlier than
waiting until a New License is received and eliminates the risk of delaying both the
construction of the new powerhouse and the completion of the required dam
improvements should the New License be delayed by intervention, appeals, or litigation.
The new powerhouse implementation plan as described in this document will minimize
interruption to downstream aquatic habitat, recreation and water supply needs since flow
disruptions only occur during the brief period of time it takes to divert flow from the
existing powerhouse to the replacement powerhouse. Duke Energy will coordinate with
the City of Morganton to minimize disruptions to the operation of their drinking water
intake downstream of the Bridgewater Development.
Beginning in October 2006, the Licensee will consult with the Parties to the Agreement
regarding the need to proceed with construction of the new powerhouse. While the
Licensee will consult with all the Agreement Parties, it will focus specifically on those
entities most directly affected by the construction of a new powerhouse including the
North Carolina resource agencies. Duke Energy will document this stakeholder
consultation and provide the FERC with a summary of stakeholder comments and
support by October 31, 2006.
9 Revised: October 2, 2006

Section 6 — Attachments
Preliminary Drawings
o Plan View
o Powerhouse Elevation View
■ Aerial View
I 1 Revised: October 2, 2006

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