Challenges With Underground High Voltage Transmission SCE Tehachapi Renewable Transmission Project First 500 kv Underground T/L in North America

Transcription

1 Challenges With Underground High Voltage Transmission SCE Tehachapi Renewable Transmission Project First 500 kv Underground T/L in North America

2 Noe Bargas, PE Supervising Senior Civil Engineer Southern California Edison Keith McCullough, Esq Alvarado Smith David Guder, SR/WA CCIM Manager, Valuation & Title Southern California Edison

3 Agenda Project Background Tehachapi Renewables Transmission Project Overhead to Underground Objectives Project Elements Duct Bank and Vault System Cable System Transition Stations Right of Way and Legal Issues/Challenges Valuation Issues Questions

4 Project Background

5 Tehachapi Wind Resource Area

6 Project Map (1 of 2)

7 Project Map (2 of 2)

8 The Renewable Portfolio Standard (RPS) In 2002, the CA Senate enacted SB 1078, mandating all Investor Owned Utilities (IOUs) to increase their renewable energy procurement to 33% by As of 8/2014: Pacific Gas & Electric 21% So Cal Edison 21% San Diego Gas & Electric 22% Cost (so far): 4 New Major Transmission Lines (const) $4 Billion 12 More Transmission Lines (planned) $12 Billion Timeline: 2009 California Public Utility Commission (CPUC) issued a CPCN to construct TRTP Segments The City of Chino Hills fought to have the 500kV lines of Segment 8 routed into the Chino Hills State Park, but the CPUC chose the route through the city instead. Construction started on the line soon thereafter. Garamendi Principles 1988

9 October 2011: SCE filed a Petition For Modification (PFM) to modify Segment 8 due to FAA recommendation regarding marking and lighting. October 2011: City of Chino Hills filed to re open the record. July 2012: SCE received orders to submit cost and design details to the CPUC by February July 11, 2013: CPUC voted 3 2* to underground a portion of Segment 8 according to Option UG 5, but did not allow the installation of 500kV reactive compensation. (*ALJ Recommends No Underground) December 2013: CPUC reinstates the reactive compensation scope to the underground line. Current Planned Operating Date: Late 2016

10 Engineering Overhead to Underground Objectives: The original design parameters were based on matching the 500kV overhead transmission lines already planned and well into construction between Mira Loma and Vincent substations. This included configuring the right of way to accommodate two 500kV underground circuits. Various cable system configurations were studied, including gas insulated lines (GIL), solid dielectric insulation cables, direct buried cables, cables in tunnels, cables in the streets. But the design team settled on cross linked polyethylene (XLPE) cables in concrete duct banks.

11 Objectives: (cont.) To minimize impacts to the community and existing infrastructure, the circuits will be installed using trenchless techniques at select areas. Transition stations on either end of the circuit would need to be constructed in very hilly terrain and a congested commercial site. The sites would need to connect to the 500kV lines already in construction. Because of the introduction of the 3.7 mile underground circuit, reactive compensation was needed. Mira Loma Sub was selected for the installation. Interconnect the underground circuit in time to meet a late 2015/early 2016 operating date.

12 Underground Configuration UG5: Single Circuit XLPE w/ 2 cables per phase, with ducts and vaults for 3 rd cable Items Unit Approximate Quantity 5000 kcmil XLPE Cable Feet 120,000 Cable Pulling Segments Each 90 Splice Vaults Each 42 (14 vault clusters, 3 vaults per clusters) Restraint Vaults Each 18 (6 vault clusters, 3 vaults per clusters) Telecom Vaults Each 32 Cable Splices Each 84 Cable Terminations Each 12 Ductbank Linear Feet 17,250 HDD Installation Linear Feet 14,500

13 500 kv UG T/L Installations Japan (in service 2000, the world s first) 24.7 miles double circuit in tunnel 5000 kcmil cable China (in service 2010) 10.6 miles double circuit in tunnel 5000 kcmil cable Russia (in service 2012) 6.8 miles double circuit directly buried 5000 kcmil cable China (in service 2014) 4.2 miles single circuit in tunnel 5000 kcmil cable

14 500 kv Cable vs. Conductor

15 500 kv Splice and Termination

16 Underground Route Terrain

17 Vault/Duct Bank/HDD Statistics 3.7 Miles (~19,500 ft) Approx. 3.2 Miles (17,250 ft) Duct Bank (open trench construction) 2 HDD Locations 6 Individual Long Bores (~2100 ft ea.) 3 Individual Short Bores (~800 ft ea.) 14 Splice Vault Clusters 6 Restraint Vault Clusters 92 Total Vaults for Single Circuit Installation 42 Splice 18 Restraint 16 Edison Carrier Solutions Telecom 16 Potential Discharge Monitoring

18 Splice Vault

19 Vault Design Considerations Use Full ROW Width

20 Overview of Transition Stations, Segment 8

21 East Transition Station

22 West Transition Station Visual Simulation

23 Right of Way Issues

24 Circa 1952

25 Today

26 Right of Way Issues WTS Access Roads Golf Course Parks Parks Road/Util Crossings 2 Flood Cntl Xings Commercial ETS

27 Golf Course

28 New Roads to Access Vaults/Landlocked Parcels

29 The Land Rights Cake Easement vs. Fee Fee Control

30 Other R/W Issues FHA Financing Road Crossings Safety Defending spurious valuation methodology (land use, listings, secondary use contracts ) Construction Safety

31 Questions?

32 FHA Addl Slides