New 230 kV Transmission Linefor Thurston County

Leslie Wright, PMPProject Manager

October 15, 2009

2

Presentation overview

Fundamentals of Electric Systems Electric System Planning Standards Thurston County Transmission Infrastructure Thurston/Pierce Electric System Thurston County Project Need Completed and Planned Transmission Projects Alternative Solutions Increased Capacity Description- New 230 KV

Transmission Line 230 kV Transmission Line Route Selection Overview Public Involvement Request

3

Fundamentals of Electric SystemsHow Power Gets To You

4

Electric System Planning StandardsNERC Regional Councils

5

Thurston County Transmission InfrastructureHow Power gets to Thurston County

6

Thurston/Pierce Electric SystemThurston and Pierce Counties

7

Thurston County Project Need

Demand for power is growing

Not enough transmission to move the power to residences and business in Thurston County

NERC reliability Without additional

transmission capacity, the delivery system will reach NERC non-compliant limits

8

Thurston County Project NeedDec 15 2008 Peak Load - Pierce/Thurston Load Trend

1050 MW Limit

1005 MW Peak

Thurston County Load

Pierce / Thurston Combined Load

9

Completed and Planned Transmission ProjectsTransmission Projects in Thurston County

Completed Projects Olympia Cut-over

Voltage upgrade to 115 kV Loss savings of 220 MWh/year Upgrade of 5 substations Re-build of 2 substations

Planned Projects Thurston / St. Clair 230 kV St. Clair – Yelm 115 kV Olympia Bus Improvements Spurgeon Creek Substation Hoffman Substation

10

Completed and Planned Transmission ProjectsTransmission Projects in Pierce County

Completed Projects Planned Projects

Woodland-St. Clair Phase I Conversion from 55 kV to 115 kV Precursor to the Olympia Cut-over Project

White River 230 kV Bus Upgrade

Alderton Transmission Station Add a new 230 kV tie to AldertonSubstation Expand Alderton Substation into a 230 kV Transmission Station

11

Alternative SolutionsTwo Paths

There are two paths to resolving the electric load requirement for Thurston County Increase capacity - Add Infrastructure Reduce demand - Increase Energy Efficiency and

Conservation

12

Alternative SolutionsIncreased Capacity Alternatives Summary

-This is an interim stop-gap solution

- May defer the larger St. Clair project by 3-5 years.

Replace existing smaller 230 kV transformer with larger capacity

Install a third 115 kV line PSE transmission in BPA Olympia

Upgrade Bulk Power Capacity in BPA Olympia

PSE has indefinitely deferred since route options are very limited …

- Resolves PSE THU capacity limitations

- Acquire about 30 miles of new 230 kV transmission route.

Complete the 230 kV White River –St. Clair project (40 miles) and install

a 230-115 kV transformer

Install 230-115 kV transformer at St. Clair

-Resolves PSE THU capacity limitations

-Not desirable since it limits the robustness of power supply into Thurston county

Construct / upgrade several PSE transmission systems

Install a 3rd 230-115 kV Bank in BPA Olympia

Install a 3rd 230-115 kV transformer at BPA Olympia

Need to Acquire about 5 miles of 100-125 ft new 230 kV transmission route

- Resolves PSE THU capacity limitations-Provides a reliable looped transmission-

Loop BPA 230 kV (about 5 miles) to St. Clair and install 230-115 kV

transformer.

Install 230-115 kV transformer at St. Clair

Route Options / ChallengesPerformance / Local PSE loadProject DescriptionOptions

13

Alternative SolutionsEnergy Efficiency and Conservation

Florescent lighting

Weatherization

High-efficiency heating and cooling

ENERGY STAR®

appliances

14

Increased Capacity DescriptionNew 230 KV Transmission Line from St. Clair Substation

15

230 kV Transmission Line Route Selection Process Overview

Identify study area Identify criteria (built environment, natural environment, and co-

location/engineering/cost) Get public input Data collection – Web Data and Field Observations Criteria weighting Process Identify route segments & candidate routes Computer Model of data, criteria and weights Quantitative and Qualitative Evaluation Selection of preferred and/or alternative routes Public Involvement Selection of preferred route

16

Route Selection Process Overview Typical Evaluation Criteria

Built Environment

• Residential dwellings• Future residential land use• Parcels• Community facilities and recreation

areas • Archaeological resource sites• Historic resource sites• Major land developments

Natural Environment

• Natural resource lands• Protected species and priority

habitats• Forest areas• Forested wetland areas• Non-forested wetlands areas• Aquifer recharge areas• Special management areas• 100-year floodplain • Shorelines• Geological hazard areas

17

Route Selection Process Overview Qualitative Evaluation

Step 2GIS Spatial Analysis of each route segment to compare route segments using

criteria.

Step 1Determine which factors have the highest priority to the project team by

summing all of the pair-wise comparisons for each criterion evaluated in the analysis.

Step 3Run model for each route segment and candidate route to produce resource

value data for the candidate route for each criterion. Apply weighting to yield preferred routes.

Routes with lowest scores have least impact. Consider other non-quantitative factors and their effect.

18

Public Involvement Request

PSE Would Appreciate Your Help To:

Identify Key Issues We Should Consider for Resolving the Thurston County Reliability Situation

Identify and Prioritize Key Factors for Corridor Siting Provide Suggestions Regarding the Public Involvement Process