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