Effect of Unit Retirements on Path Ratings & Planning Process Gap

1. Effect of Unit Retirements on Path Ratings & Planning Process Gap Brian Keel

2. 2 Topics: • Path Rating impacts by loss of fossil generation • Gap in Planning and Operating Project Development Process

3. Path Rating impacts by loss of fossil generation MOD – 029 or TTC for Path Rating • Base load generation scenarios studied • If resource diminished at sending end of Path being studied, reductions of the Path Rating are possible, transition from Reliability Limit to Flow Limit • Applicable to Coal, once- throughs, nuclear, etc.

4. D E Coal Plants 2 Lines Fossil Injection A B C Grandfathered Grandfathered

5. WECC Paths • MOD – 029 Studies, if Reliability limited Path, with Resource reduction becomes a Flow Limited Path, TTC determined as Facility Rating • With (MOD – A above is an allowed technique) This means TTC can use the Facility Rating, or now TTC increases! • Is this reasonable?

6. WECC Paths • Grandfathered Paths: • With Parallel Paths, how are the Resources distributed? • Are the grandfathered Paths held whole 1st? • Meaning their rating held 1st? • Meaning if I do not have Grandfathered Path then always have to observe G Paths, then can flow on non G Path • With reduced TTC values, • Is the reduced TTC now a latent capacity that another resource developer can exploit? • Exploit =inject their generation and then claim the increased TTC as theirs?

7. WECC Paths • Is this to be determined in each PRG or • Do we need WECC 3 Phase Rating Policy?

8. EOR Path Representation Navajo Crystal Eldorado Moenkopi Mead EOR Path Mead Peacock Perkins Westwing Liberty Colorado River Red Bluff Devers Palo Verde Hassayampa Imp. Vly N. Gila Hoodoo Wash Existing 500kV Stations Existing 345kV Stations Existing 500kV Lines Future 500kV Lines Future 500kV Stations Future Gen. Stations

9. Introduction Southern California Edison Co. (SCE) is currently constructing a 110 mile, 500 kV transmission line from SCE’s new Colorado River Substation near Blythe, California to SCE’s Devers Substation near Palm Springs, California The name of the project is Devers – Colorado River (DCR) Due to change of system configuration, SCE proposed Path 49 (EOR) and Path 46 (WOR) re-definition and upgrade The Three Phase Rating Process conducted by SCE concluded that WOR is upgradable from 10623MW to 11200MW and EOR is upgradable from 9300MW to 9600MW

10. Impact of the Future Generation Interconnecting Red Bluff and Colorado River Stations SCE performed the Three Phase Rating Process and proved that due to system configuration changes with the addition of DCR, both Path 46 and Path 49 ratings can be increased Sensitivity study showed that with the future maximum generation of 4000MW at Red Bluff and Colorado River, EOR cannot flow more than 5240MW The CAISO explained that this kind of interaction will be resolved through the operating studies.

11. Impact of the Future Generation Interconnecting Red Bluff and Colorado River Stations • In n-0 condition, may have overload of NG line because of re-distributed line flow because of Receiving end generation • Or n-1 of Northern EOR Component • Curtail steps to include • Reduce NG schedules or all of EOR, but if not enough, where to cut next? • How determined? • SRP has following concerns and questions: • Who identifies when interaction between new generation at Red Bluff and Colorado River and EOR creates congestion? • What kind of mechanism will be in place between generation owners and EOR path operator in order to mitigate these problems and who gets curtailed first ? • Concern is not having local generation curtailed for CA overloads