Renewables and the Smart Grid Trip Doggett President & CEO Electric Reliability Council of Texas
North American Interconnected Grids The ERCOT Region is one of 3 North American grid interconnections. The ERCOT grid: Covers 75% of Texas land Serves 85% of Texas load 38,000 miles of transmission lines >550 generation units Physical assets are owned by transmission providers and generators, including municipal utilities and cooperatives 65,776 Megawatts peak demand (set 8/23/2010) ERCOT connections to other grids are limited to direct current (DC) ties, which allow control over flow of electricity
And we re excelling at integrating variable resources 12,000 MW 10,000 8,000 Cumulative Planned (Signed Interconnection Agreement) Cumulative MW Installed ERCOT is #1 in the U.S. in wind production. 8,005 8,916 9,467 150 9,617 300 10,209 10,209 10,445 892 892 1,128 6,000 Our capacity is three times the amount of #2 (Iowa). 4,000 If Texas were a separate country, we d be #5 in the world. 2,875 4,785 9,317 9,317 9,317 9,317 9,317 2,000 816 977 1,173 1,385 1,854 0 116 116 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Year as of July 31, 2010
But every day it s a balancing act 70,000 5000 65,000 4500 60,000 4000 55,000 3500 Load MW 50,000 45,000 3000 2500 Wind MW 2000 40,000 1500 35,000 1000 30,000 500 25,000 8/9/10 8/9/10 8/10/10 8/10/10 8/11/10 8/11/10 8/12/10 8/12/10 8/13/10 8/13/10 8/14/10 8/14/10 8/15/10 8/15/10 8/16/10 8/16/10 0 Integrated Load Actual Integrated Wind Output
Winter Day Load Shape with Fuel Mix
Generation Output by Fuel High Daily Wind Output March 5. 2010 Wind Other Hydro Gas Coal Nuclear Wind Gas 80,000 10,000 70,000 9,000 8,000 60,000 7,000 50,000 6,000 40,000 5,000 30,000 4,000 3,000 20,000 2,000 10,000 1,000 0 0 0:15 1:15 2:15 3:15 4:15 5:15 6:15 7:15 8:15 9:15 10:15 11:15 12:15 13:15 14:15 15:15 16:15 17:15 18:15 19:15 20:15 21:15 22:15 23:15
Wind Generation Correlation with Demand by Zone Based on data from July 1-21, 2009 Correlation Coefficient between ERCOT System Load and Wind Output in Zone: West: -0.243 South: 0.656
Operational Challenges Day-Ahead Wind Forecast Accurate forecast of wind generation for the next day is necessary when planning for the next day Developing Improved Wind Forecast tool Training Operators on Operator Training Simulator for high wind variation scenarios Creating risk assessment tool which assesses risk of varying wind/load/outages and advises operator when mitigation required Frequency Control With increased amount of variable wind resources the possibility of missing the forecast need for Balancing Energy and running out of Regulation Reserves to control frequency is higher. Many wind Resources are capable of going between full load and zero in 30 seconds; much faster than conventional units providing frequency regulation. Implemented ramp rate restrictions on wind generation Perfecting wind ramp forecaster Reactive Capability Conventional synchronous generating units utilize a fairly standardized Automatic Voltage Regulator technology to provide voltage control automatically. Older (Inductive) wind units have to provide reactive with external switching devices while new (asynchronous) wind units can provide reactive capability through internal power electronics. Performing dynamic reactive studies in wind regions Installing measurement system and use phasor measurements to validate dynamic studies Low Voltage Ride Through Technologies in wind generators have varying capabilities for remaining online through brief dips in transmission voltage. Require low voltage ride through for all new units Studies determined existing units do not need to retrofit low voltage ride through capability.
Provided by AWS Truewind Wind Generation Resource (WGR) Power Forecasting Two forecasts are produced for each WGR The Wind Generation Resource Production Potential (WGRPP) is an 80% probability of exceedence forecast The Short-Term Wind Power Forecast (STWPF) is the most likely or 50% probability of exceedence forecast Aggregate Wind Power Forecasts: Red = STWPF, Green = WGRPP Each hour a new forecast is created for the next 48 hours Aggregate forecasts are also created and sent to ERCOT
ERCOT Large Ramp Alert System (ELRAS) System awareness tool provided by AWS through a web interface Utilizes the same data that is being provided by ERCOT for the wind power forecasts Includes the following: An estimation of the probability of a defined ramp event (i.e. 1000 MW up ramp in a hour) beginning in a particular interval Information regarding the weather event which is most likely to cause the ramping event (i.e. a cold front) Additional attributes for each predicted ramp event including most likely start time, duration and maximum ramp rate Time variant graphics to provide additional situational awareness Looks from the current time to 6 hours into the future
Operator s View - 3/1/10 Forecast at 04:00
Causes of the Sixty Largest ERCOT Wind Power Ramps January 1 to April 20, 2009 Down Ramps Up Ramps Coid Front - Up Ramp Low Level Jet - Up Ramp Pressure Gradient Change - Up Ramp Daytime Mixing - Up Ramp Dry Line - Up Ramp Pressure Gradient Change - Behind Cold Front - Down Ramp Pressure Gradient Change - High Pressure - Down Ramp Pressure Gradient Change - Other - Down Ramp Nocturnal Stabilization - Down Ramp Low Level Jet - Down Ramp Ramp events have different meteorological causes and thus the optimal parameters for tracking and predicting them are different
Accuracy of Data is Important Example, Percent of Total WGR CAPACITY w/valid Met Data for all Points 100% 90% 10-07-2010 86% 80% 70% 60% 50% 40% 1-Jun-10 1-Jul-10 1-Aug-10 1-Sep-10 1-Oct-10
Our market is building transmission faster than any other There are 44,233 Miles of Transmission Lines in Texas 9,582 Miles of 345kV Lines 19,650 Miles of 138kV Lines 7,134 circuit miles of transmission built since 1999 7,867 circuit miles of transmission under study $5.9 b investment in transmission placed in service since 1999 $9.4 b under development (including CREZ transmission)
Scenario 2 Transmission Plan (18GW) 2334 mi. new 345kV ROW 42 mi. new 138kV ROW
Designated Zones and Scenario Wind Levels Capacity of New CREZ Wind for Scenario 2 (MW) Wind Zone Scen. 2 Panhandle A 3,191 Panhandle B 2,393 McCamey 1,859 Central 3,047 Central West 1,063 Total* 18,456 * Assumes 6,903 MW of existing wind capacity at time study was performed
What is it Going to Cost? CREZ projects will cost about $5 billion over the next 5-8 years Other non-crez projects will cost about $3 billion over the next 5 years Transmission projects completed in 2008 totaled over $574 million Transmission projects completed in 2009 totaled over $736 million
Today, we re settling more than a million advanced meters AMS Meter Deployment Plan Settlement Using AMS First Operating Day Settled Using Advanced Meters: November 29, 2009 263 ESIIDs 18
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