Buffalo Ridge Incremental Generation Outlet (BRIGO)
Transmission Study
Presentation to National Wind Coordinating Committee
June 22, 2005
W Grivna, PE of Xcel Energy
R Gonzalez, PE of Excel Engineering, Inc.
Outline
• Study Purpose/Goals• Background• Participants• Analysis• Results• Conclusions/Recommendations• Next Steps
Study Purpose/Goals
• Determine feasibility of increasing Buffalo Ridge area generation outlet…
• by several hundred MW…• through “modest” (presumably 115 kV-class)
improvements…• that could be relatively quickly implemented…• while plans for future long-range regional
transmission projects continue their evolution.
Background• Buffalo Ridge is the premier wind resource in
MN/SD• Transmission improvements under way to increase
outlet capacity to 825 MW• Further interest confirmed by MISO & WAPA
interconn queues• Xcel Energy has had specific MW & Energy %
mandates• All other Minnesota power suppliers now also
have renewable energy obligations• Result: Intense interest in wind development on
the Ridge
Transmission map of Buffalo Ridge Area
Study Participants
• Sponsor: Xcel Energy
• Technical & Economic Analyses performed by Xcel Energy
Reviewers/technical support: (MAPP MB SPG)
• Western Area Power Administration• Otter Tail Power• Missouri River Energy Services• MISO• Marshall Municipal Utilities• Great River Energy• East River Electric Power Cooperative• Alliant Energy• State regulators (MN/ND/SD)• Energy Policy Groups (Wind on the Wires)• IPPs
Analysis• Powerflow: Concentrate on 2007, summer off-
peak condition– System intact– First contingency (“n-1”)
• Requirement: satisfy applicable voltage and loading criteria
• Identify “existing system” (post-825 MW additions) outlet limits for Buffalo Ridge Mpls/St Paul deliveries
• Formulate transmission options• Test Options’ performance
– Electrical– Financial
Cost versus Outlet for Options
Complications
• Reactive power requirements/Voltage Stability• Power and Energy losses• Load-serving considerations• Constructability• MISO-WAPA interface• North Dakota Export (NDEX) interface• Geographic extent of Ridge
Results• All Options can achieve 300-500 MW of
incremental outlet• Some Options require extensive additional
improvements– Line reconductors & rebuilds
– Transformer replacements
– Shunt capacitor additions
• Incremental energy losses are high (25 – 30%)• The “best” Options all include a second
(independent) Fenton-Nobles Co 115 kV outlet path to the new 345 kV
Conclusions/Recommendations
• Implement “Option 31A”– 2nd Nobles Co 345/115 kV transformer– 2nd Nobles Co-Fenton 115 kV line– Lake Yankton-Marshall 115 kV line– Several shunt capacitor banks– Misc reconductors, equipment upgrades
• Capable of providing 300 - 500 MW of incremental outlet (beyond 825 MW level) at reasonable cost
• Provides some incidental load-serving benefits
Map of Option 31A
Next Steps• Coordinate & confirm compatibility with likely
long-range plans & identified projects– CapX– Big Stone 2– MISO NW Exploratory
• Address adaptation to specific proposed wind gen projects
• (Need “Yankee fix” if MWs on north Ridge exceed critical level)
• Coordinate with MISO stability study results• Initiate permitting process
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