Centralia Power Plant Closure Study. Initial Study Results DRAFT. March 17, 2011

Transcription

1 Centralia Power Plant Closure Study Initial Study Results DRAFT March 17, 2011

2 Conditions Studied 5 and 10-year Winter and Summer Peak 5-year Light Autumn High Transfers to and from British Columbia Additional gas-fired generation taken off-line to stress system

3 Centralia Closure Timing Initial Studies Both units closed in 2015 Both units closed in 2020 Recent Agreement First unit closed in 2020 Second unit closed in 2025 Studies do not need to be rerun but the report will be written based on the recent agreement

4 Centralia Replacement Alternatives 1. Replace Centralia with power from California. 2. Replace Centralia with power from eastern Washington/Idaho (e.g. Lower Snake). 3. Replace Centralia with power from new local generators at Kalama (700 MW) and Grays Harbor (700 MW). 4. Replace Centralia with power from new local generators on site at Centralia (2-700 MW combined cycle plants). 5. Replace Centralia partially with power from a new local generator on site at Centralia (1-700 MW combined cycle plant) and partially with generation from eastern Washington/Idaho (e.g., Lower Snake). 6. Replace Centralia by increasing generation at other west-side plants. 7. Replace Centralia by increasing all Northwest generators in proportion to their rating up to their maximum capability. 8. Replace Centralia by increasing all WECC generators in proportion to their rating up to their maximum capability. Note: Alternatives in blue have not been studied yet

5 Transmission Project Sensitivities Only McNary-John Day was included in the initial simulations

6 Results At this point, transmission issues have only been identified for cases where Centralia generation is replaced from the east or from California

7 Three Main Transmission Issues Issue 1: Overloading concern s in the Portland area during light load periods with high level s of transfers to British Columbia and low level s of west-side gas generation Issue 2: Overloading concern s in the Tacoma/Olympia area (Raver-Paul) during high level s of transfers from British Columbia and low level s of west-side gas generation Issue 3: Increased usage of the West of Cascades North and South transmission paths which can be a concern during winter peak load periods, particularly during high level s of transfers to British Columbia

8 Issue 1 Overloading concerns in the Portland area during high levels of transfers to British Columbia and low levels of west-side gas generation during light load periods

9 Concern: An outage of the Keeler- Pearl 500 kv line can overload the Murray Hill-Saint Mary s 230 kv line and some underlying 115 kv lines Conditions: High south to north transfers and light load conditions

10 Calculated loading on the Murray Hill-Saint Mary's 230 kv line following the outage of the Pearl-Keeler 500 kv line 800 Winter emergency rating 600 Summer emergency rating Up to a 220 MW increase With Centralia off-line and replaced from John Day area MW With Centralia on-line based on actual operation during Summer emergency rating -600 Winter emergency rating (8760 hours stacked by magnitude)

11 Concern: An outage of the Pearl- Marion and Pearl-Ostrander 500 kv lines can overload the McLoughlin-Pearl 230 kv line. Conditions: High south to north transfers

12 Issue 2 Overloading concerns in the Tacoma/Olympia area (Raver- Paul path) during high levels of transfers from British Columbia and low levels of west-side gas generation

13 Concern: An outage of the Raver- Paul 500 kv line and the Covington-Chehalis 230 kv line can overload the South Tacoma-Saint Clair 230 kv line and some underlying 115 kv lines Conditions: High north to south transfers

14 Issue 3 Increased usage on the West of Cascades North Path during winter peak load periods

15 Concern 1: An outage of the Shultz-Echo Lake and Shultz- Raver 500 kv lines can lead to voltage collapse Concern 2: An outage of the John Day-Marion and Buckley- Marion 500 kv lines can lead to voltage collapse

16 West of Cascades Paths The West of Cascades North path was found to be more limiting than the West of Cascades South path The Total Transfer Capability of the paths may not change significantly with the closure of Centralia but this remains under study. Path usage can be significantly affected if the replacement resource is on the east side of the Cascades The West of Cascades North path could see increases of MW following the outage of each Centralia unit if replaced from the east. The further north the replacement (Chief Joseph versus COI), the greater the impact. Replacing with resources from the John Day area would lead to an increase in West of Cascades North flow of approximately 300 MW for each Centralia unit. Additional west-side resources would help defer the need for new transmission investment across the Cascades

17 Note: This graph assumes that Centralia is replaced with resources from the John Day area. If Centralia is replaced with west side generation then there would not be this impact.

18 Northwest Wind Resources Most new resources are located in the east and would need to used the West of Cascades transmission paths to reach the west-side load centers 18

19 Transmission Project Sensitivity Results Cascade Crossing Project Adds transmission capacity to the West of Cascades South transmission path but does very little for the West of Cascades North Path I-5 Corridor Reinforcement Project Helps to mitigate transmission overloading concerns in the Portland area Big Eddy-Knight No significant effects Trojan-Horizon 230 kv No significant effects Hemingway-Boardman No significant effects Central Ferry-Lower Monumental No significant effects

20 Potential Mitigation Options (yet to be fully studied) Identified problems can be addressed by increasing existing west-side generation levels, adding new west-side generation, and/or curtailing transfers to or from British Columbia Contractual agreements would likely be required for redispatch Cost is unknown but could be substantial This option could make it more difficult to meet RPS goals due to the need to run west side gas generation Portland Thermal overloading could be corrected by: Reconductoring facilities; or, Adding a second Murray-Saint Mary s 230 kv line; or, I-5 Corridor Project Tacoma/Olympia (Raver-Paul path) overloading could be corrected by: Reconductoring facilities; or, Second Raver-Paul 500 kv line Adopt a potential change in reliability criteria that has been recently proposed to WECC where only lines greater than 300kV would need to be considered to meet the adjacent circuit criteria. Cross Cascades Voltage Stability South Path: Reactive power additions and/or Cascade Crossing Project North Path: BPA series capacitor addition project and potentially a new line across the Cascades or from eastern Washington to British Columbia

21 Next Steps Complete analysis Develop recommendations for which projects, if any, should move forward Complete report