East Texas Export Limit ERCOT Operations Planning ERCOT Market Presentation

Outline Basis for GTL Study Results ERCOT steps to implementation

Stability limit Overview Clearances can create a stability limit. –N-1 in the base case + single-line-to-ground fault breaker stuck event

SOP-110 Overview Under planned or forced 345kV outages. Outages –Martin Lake – Tyler Grande 345 kV –Tyler Grande – TriCorner 345 kV –Martin Lake – Shamburger 345 kV –Shamburger – Royce 345 kV –Martin Lake – Elkton 345 kV –Elkton – Forney 345 kV –Martin Lake – Stryker 345 kV –Stryker – Trinidad 345 kV –Mt. Enterprise – Trinidad 345 kV

SOP-110 Overview GTL Limit 345-kV Line OutageInterface Limit Martin Lake – ShamburgerInterface Flow* less than 1900 MW Martin Lake – Tyler GrandeInterface Flow less than 1900 MW Mt. Enterprise – TrinidadInterface Flow less than 1900 MW Martin Lake – ElktonInterface Flow less than 2300 MW Martin Lake – StrykerInterface Flow less than 2300 MW Tyler Grande – TriCornerInterface Flow less than 2300 MW Shamburger – RoyseInterface Flow less than 2300 MW Elkton – ForneyInterface Flow less than 2300 MW Stryker -- TrinidadInterface Flow less than 2300 MW *The interface is consisted of six 345-kV lines: MartinLake – Shamburger, MartinLake – TylerGrande, MartinLake – Elkton, MartinLake – Stryker, MtEnterprise – Trinidad, MtEnterprise – Nacogdoches

SOP-110 GTL Overview GTL Limit An Interface has been tested in the EMS to verify ERCOTs ability to monitor the flows

SOP-110 GTL Overview GTL Limit ERCOT TCM has been tested to ensure the interface can be passed to SCED with the relevant shift factors. SCED processing has been confirmed via testing. Active and Inactive Network Security Constraints were checked and this will be posted in MIS when the constraint is active.

SOP-110 GTL Overview GTL Limit

SOP-110 GTL Overview Total generation capacity: 3250 MW Any one of nine 345kV line outages listed in the SOP- 110 will enforce the limit.

GTL steps taken ERCOT worked with Oncor in 2012 to reduce the breaker time from 14 cycles to 10 cycles for the critical contingency. Generator has provided updated dynamic model and GSU limits for units. ERCOT Planning completed study with limit provided to Ops Ops has built the interface and tested it.

GTL next steps ERCOT presentation to CMWG. Post GTL for comments. Target GTL implementation date of Dec