The (Continuing) Evolution of the ERCOT System Dan Woodfin Sr. Director, System Operations, ERCOT PUBLIC
The ERCOT Region The interconnected electrical system serving 90% of Texas load, with limited external connections • 73,308 MW peak demand (July 19, 2018) • More than 46,500 miles (75,000 km) of transmission lines • 610+ generation units 220 MW with SPP 600 MW with SPP ERCOT connections to other grids are limited to ~1250 MW of direct current (DC) ties, which allow 30 MW with Mexico control over flow of electricity at Eagle Pass 100 MW with Mexico at Laredo 300 MW with Mexico at McAllen TSDOS 9/6/18 2 PUBLIC
ERCOT Inc. • As a part of the restructuring of the Texas electric market in 1999, ERCOT was assigned four primary responsibilities by the Texas Legislature: • Maintain system reliability • Facilitate competitive wholesale market • Ensure open access to transmission • Facilitate competitive retail market • ERCOT is regulated by the Texas Public Utility Commission (PUC) with oversight by the Texas Legislature. ERCOT is not a market participant and does not own generation or transmission/distribution wires. TSDOS 9/6/18 3 PUBLIC
Current Demand Records Peak Demand Record: 73,308 megawatts (MW) Recent Monthly Peak Demand Records • July 19, 2018, 4-5 p.m. 2018 • January: 65,915 MW (Jan. 17, 7-8 a.m.) Weekend Peak Demand Record: 71,445 MW • May: 67,265 MW (May 29, 4-5 p.m.) • Sunday, July 22, 2018, 5-6 p.m. • June: 69,102 MW (June 27, 4-5 p.m.) Winter Peak Demand Record: 65,915 MW • July: 73,308 MW (July 19, 4-5 p.m.) • Jan. 17, 2018, 7-8 a.m. 2017 • April: 53,486 MW (April 28, 4-5 p.m.) • July: 69,512 MW (July 28, 4-5 p.m.) • October: 62,333 MW (Oct. 9, 4-5 p.m.) *New records are preliminary, subject to change in final settlement TSDOS 9/6/18 4 PUBLIC
Evolving Resource Mix PUBLIC
Wind Generation Capacity – July 2018 Wind Generation Records (instantaneous) • Output: 17,541 MW ‒ Feb. 19, 2018, 10:05 p.m. • Penetration (load served): 54% ‒ Oct. 27, 2017, 4 a.m. ‒ Total Load = 28,416 MW • Texas continues to lead U.S. in wind capacity. • Not all planned projects will be built; incentives, uncertainty and other factors affect construction decisions and schedules. Future outcomes uncertain TSDOS 9/6/18 6 PUBLIC
ERCOT Installed Capacity (1999-2018) 1.1% 100,000 • Wind and solar values are based on nameplate capacity (not adjusted for peak capacity contribution) • Private Use Network capacity not included 21.0% 80,000 6.6% 0.3% 12.4% 60,000 5.3% 51.6% 35.9% 40,000 0.8% 4.8% 20,000 1.0% 28.6% 16.9% 8.4% 5.3% 0 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Nuclear Coal Other Gas CC Gas Steam Gas CT/IC Wind Solar TSDOS 9/6/18 7 PUBLIC
Changing Resource Capacity Mix Solar Other Other Solar Wind 1% 0% 1% 1% Gas CT/IC 0% 5% Nuclear 5% Nuclear 8% Wind Coal 21% 17% Coal 29% 1999 2018 Gas CT/IC 7% Gas Steam 52% Gas Steam 12% Gas CC Gas CC 5% 36% TSDOS 9/6/18 8 PUBLIC
Real-Time Operations and Market • Market participants bring generation on-line; ERCOT may start additional generation needed to maintain reliability. • Market participants submit offers for generation output. • ERCOT clears the market every five minutes, using the generation with the lowest bids to serve the load, subject to transmission constraints. • Prices received by generators signal whether more or less output is needed from generators in that area at that time. • In general, the set of generator output levels produced by this process is the lowest cost way that $2.54 $86.4 doesn’t overload the transmission system 6 Prices to meet the system load for each five minute interval. TSDOS 9/6/18 9 PUBLIC
Peak Demand Day (7/19/18) – Generation by Fuel Type TSDOS 9/6/18 10 PUBLIC
High Wind Day (2/19/18) – Generation by Fuel Type TSDOS 9/6/18 11 PUBLIC
Evolving Transmission PUBLIC
Major Transmission Additions ~2007-2018 TSDOS 9/6/18 13 PUBLIC
Major Future Transmission Improvements - Panhandle Panhandle Projects • Scheduled for completion in 2018 • Addresses export capacity for growing wind resources and weak grid conditions Index Transmission Improvement 1 Alibates Synchronous Condenser 2 Tule Canyon Synchronous Condenser 3 Alibates-AJ Swope-Windmill Ogalalla- Tule Canyon 345 kV Circuit Addition TSDOS 9/6/18 14 PUBLIC
Major Future Transmission Improvements - Lubbock Lubbock Integration • Portion of Lubbock Power and Light load switching into ERCOT • Approximately 490 MW of summer peak load • Network of primarily 115-kV lines connected by multiple 345-kV lines • Scheduled for completion in 2021 • New 345kV transmission lines needed; will also provide new export capacity from Panhandle TSDOS 9/6/18 15 PUBLIC
Major Future Transmission Improvements - Far West ERCOT Anticipated Service Transmission Improvement Project Endorsement Dates Line 69H Rebuild and 138-kV Conversion Project October 2016 June 2018 Permian Basin-Solstice 138-kV line rebuild October 2016 February 2019 Riverton-Sand Lake 138-kV line (new) November 2016 May 2019 Far West Texas Project 1.0 (New Odessa-Riverton and May 2020 / June 2017 Bakersfield-Solstice 345-kV lines) April 2021 Far West Dynamic Reactive Devices June 2018 May/ December 2019 Far West Texas Project 2.0 (New Riverton-Sand Lake-Solstice 345-kV line and Kyle Ranch-Riverton and Horseshoe Spring- June 2018 December 2020 Riverton 138-kV lines) TSDOS 9/6/18 16 PUBLIC
Continuing Changes PUBLIC
Utility Scale Solar Generation Capacity – July 2018 Future outcomes uncertain TSDOS 9/6/18 18 PUBLIC
Interconnection Studies – July 2018 FIS IA Executed, Pending or FIS Pending Screening Completed or Approved Fuel Type Study (MW) (MW) (MW) Total (MW) Gas- All Other 0 779 1,972 2,751 Gas- Combined Cycle 3,292 2,046 3,165 8,503 Gas- Compressed Air 0 0 324 324 Total Gas 3,292 2,825 5,461 11,578 Nuclear 0 0 0 0 Coal 0 0 0 0 Wind 7,624 18,046 12,027 37,697 Battery 322 200 0 522 Solar 8,186 19,318 2,551 30,055 TSDOS 9/6/18 19 PUBLIC
Geographic Spread of Solar Interconnection Studies TSDOS 9/6/18 20 PUBLIC
Forecasting 3HR Ahead Forecast Errors - 2017 Load Higher than Forecasted Load Lower than Forecasted Wind Lower than Wind Higher than Forecasted Forecasted TSDOS 9/6/18 21 PUBLIC
Evolving Ancillary Services Needs • Ancillary Services are procured to ensure extra capacity is available to address variability that cannot be covered by the five-minute energy market. – Instantaneous Load Variation – Changes in variable generation output – Generators tripping offline – Forecast errors • Ancillary Services designs and quantities continue to evolve to meet changing system needs and resource capabilities TSDOS 9/6/18 22 PUBLIC
Addition of Flexible Gas Units TSDOS 9/6/18 23 PUBLIC
Emerging Issues PUBLIC
DER Visibility • DER >1 MW must register with ERCOT Based on this info, we – If it injects to the grid; and estimate : – Is not registered with PUC as Self- • Units <1 MW Generation – About 30,000 units (mainly rooftop solar) • Investor-owned TDSPs submit – About 250 MW – Annual DER interconnection reports to PUC • Units >1 MW – Regular updates to ERCOT Profile Codes – 140 units (~90% diesel or natural gas) • Munis and Co-ops (NOIEs) report: – More than 850 MW – Aggregated data on units >50 kW that inject energy to the grid – Some anecdotal summaries to City Councils, etc. TSDOS 9/6/18 25 PUBLIC
DER Improvements for Transmission Operations Modeled Equipment • Improved reporting • Mapping of Registered DERs to the Line-1 Line-2 transmission grid – Requires cooperation among TSPs, CB-1 CB-2 DSPs and the ISO – Underway now • Nodal pricing for larger DERs – Local price signals would enhance reliability and would Load-1 Load-2 align DER behavior with overall market design • Incorporate mapped DER info into Mapped Information DG-1 ERCOT processes – e.g. forecasting, powerflow studies, dynamic analyses, A/S requirements, etc. TSDOS 9/6/18 26 PUBLIC
Storage Interconnection Requests 2022 2021 2020 • Preliminary Data • 2019 Some of these requests were previously included within other GINRs • Not all planned projects will be built; incentives, uncertainty and other factors affect construction 2018 decisions and schedules 0 500 1000 1500 2000 2500 3000 Operational Signed IA FIS Requested Initial Request TSDOS 9/6/18 27 PUBLIC
“Weak System” Inverter Instability • In areas with no conventional generation, very little load • Electrically far from the rest of system (synchronous units), perhaps during outage • Dynamics dominated by power electronics (wind plants, SVC.) • Disturbances occurring when the Weighted Short Circuit Ratio (WSCR) is below 1.5 can cause control system instability for inverter-connected resources. • Ability to use of WSCR as measure of the potential for this instability may not be uniform TSDOS 9/6/18 28 PUBLIC
Increased Complexity of Required Studies TSDOS 9/6/18 29 PUBLIC
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