Grid Operations and Planning

Grid Operations and Planning Report Kent Saathoff ERCOT Board of Directors April 20, 2010 Kent

Content Summary March 2010 Operations Peak Demand: Actual vs. Forecast On-line Resources: Total at Peak and Wind Day-Ahead Load Forecast Performance Out of Merit Capacity Order (OOMC) & Replacement Reserve (RPRS) Purchases Zonal Congestion Significant System Incidents Advisories, Watches and EEAs Other Items Planning Activities Summary Generation Interconnection Requests Wind Capacity 2 ERCOT Public

Summary March 2010 Operations The peak demand of 41,416 MW on March 2 nd was less than the long term forecast peak of 41,448 MW but more than the March 2009 actual peak demand of 40,289 MW. Day-ahead load forecast error for March was 2.74%. Advisories for Adjusted Responsive Reserve (ARR) below 3000 MW issued 10 days No Watches for ARR under 2500 MW No Energy Emergency Alert (EEA) events One Transmission Watch issued 220 active generation interconnect requests totaling over 73,000 MW as of March 31, 2010. One request more than February 28, 2010 9,117 MW wind capacity on line March 31, 2010. Increase of 201 MW from February. 3 ERCOT Public

March 2010 Daily Peak Demand: Hourly Average Actual vs. Forecast, Resource Plan & On-line Capacity at Peak 50,000 Actual Peak Load 45,000 Peak Demand for the Month: 41,416 MW @ 03/02/10 HE08:00 Actual Online Capacity Actual Wind Output ERCOT Load Day-Ahead Forecast Wind Day-Ahead Resource Plan 40,000 35,000 30,000 MW 25,000 20,000000 15,000 10,000000 5,000 0 Note: All data are hourly averages during the peak load hour obtained from Resource Plans, and EMMS. 4 ERCOT Public

March 2010: Actual Wind Output w/ Curtailment Added Back Vs Wind Day-Ahead Resource Plan Based on AWS Forecast for All Hours 7000 6000 % of Hours with Output + Wind Curtailments >= Resource Plan MW (Target = 80%) 77.93% 5000 Daily Averaged Wind Curtailment 4000 MW 3000 Daily Averaged Aggregate Wind Output 2000 Daily Averaged Day Ahead Resource 1000 Plan 0 Date Note: QSEs must use AWST 80% probability of exceedence forecast for Day-Ahead Resource Plans 5 ERCOT Public

March 2010: Monthly Peak Demand: Actual 70,000 Peak Demand is Peak Interval Demand 60,000 2009 2010 50,000 40,000000 MW 30,000 20,000 10,000 - Month 6 ERCOT Public

March 2010: Monthly Minimum Demand: Actual 35,000 Minimum Demand is Valley Interval 30,000 2009 2010 25,000 20,000 MW 15,000 10,000 5,000 - Month 7 ERCOT Public

Day-Ahead Load Forecast Performance in March 2010 Mean Absolute Percent Error (MAPE) for ERCOT Mid-Term Load Forecast (MTLF) Run at 16:00 Day Ahead 2007 2008 2009 2010 March 2010 MAPE MAPE MAPE MAPE (YTD) MAPE Average Annual MAPE 3.55 3.30 3.11 3.27 2.24 8 ERCOT Public

Capacity Purchases of RMR, OOMC & RPRS to Manage Local Congestion in March 2010 70 60 RMR OOMC RPRS S1 RPRS S2 50 40 Unit-Days 30 59 ` 20 10 0 10 8 2 7 2 2 1 1 1 1 DFW W RIO Western Austin North San Antonio Houston 9 ERCOT Public

Zonal Congestion CSC March 09 Days Jan 10 Days Feb 10 Days March10 Days Last 12 Months Total Days (March 09 March 10) North Houston 9 1 0 0 52 North West 2 0 0 0 2 West North 13 13 12 24 155 Mar 1, 3-15,18-20, 22, 26-31 South North 3 0 0 0 9 North - South 7 1 0 0 38 10 ERCOT Public

Significant System Incidents in March 2010 March 20 th Simultaneous loss of five wind units, two auto transformers and one 345 kv line. Line under construction fell into energized line due to high winds March 24 th Simultaneous loss of five wind units, two auto transformers and one 345 kv line. Thunderstorms in area. Still under investigation. March 31 st ERCOT lost connection to the Market Management System (MMS). Held interval ending 00:30 balancing energy deployment and resumed with interval ending 01:30 deployment. 11 ERCOT Public

Advisories and Watches in March 2010 Advisories issued for Adjusted Responsive Reserve (ARR) below 3000 MW. Issued 10 Days. Watches issued for Adjusted Responsive Reserve (ARR) below 2500 MW. None Transmission Watches March 31 st ERCOT issued a Transmission Watch issued due to the forced outage at tgails substation. ti Implemented Block Load Transfer up to 2 MW from ERCOT (Gails substation) to SPP (Draw substation). No EEA s in March 2010 12 ERCOT Public

Other Items March 19 th Held Real-Time Balancing Market for interval ending 20:00 due to incorrect offset value entered. Resumed with interval ending 20:30 deployments. March 20 th Held Real-Time Balancing Market for interval ending 23:00 due to 23:15 deployments going out late. Resumed with interval ending 23:30 deployments. March 27 th Held Real-Time Balancing Market for interval ending 20:15 due to incorrect offset value entered. Resumed with interval ending 20:45 deployments. 13 ERCOT Public

Planning Summary ERCOT is currently tracking 220 active generation interconnection requests totaling over 73,000 MW. This includes almost 45,000 MW of wind generation. Regional Planning is currently reviewing proposed transmission improvements with a total of $798.0 Million Transmission Projects approved in 2010 total $0 Million All projects (in engineering, routing, licensing and construction) total approximately $9.6 Billion Transmission Projects energized in 2009 total about $762 million Transmission Projects energized in 2010 total about $41.3 million 14 ERCOT Public

County Location of Planned Generation with Interconnection Requests (all fuels) March 2010 15 ERCOT Public

County Location of Planned Generation with Interconnection Requests (Wind) March 2010 16 ERCOT Public

Wind Generation MW 12,000 10,000000 Cumulative Planned (Signed Interconnection Agreement) Cumulative MW Installed 8,916 9,865 748 10,441 1,324 10,992 10,992 1,8 875 1,8 875 8,000 8,005 6,000 4,785 4,000 9,117 9,117 9,117 9,117 2,875 2,000 816 977 1,173 1,385 1854 1,854 0 116 116 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Year as of March 31, 2010 ERCOT Public 17

Generation Interconnection Activity by Fuel MW Natural Gas MW Nuclear MW Coal MW Wind MW Solar * MW Biomass * MW Other Total # Projects # Projects Cancelled 120,000 * Prior to September 2008, Category "Other" included "Solar" and "Biomass" Projects in all phases of interconnection study are reflected in this graph Project cancellation tracking by month began in March 2008 300 100,000 250 80,000 200 Project Count 60,000 150 MW Capacity 40,000 100 20,000 50 0 0 Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07 Jul-07 Aug-07 Sep-07 Oct-07 Nov-07 Dec-07 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 18 ERCOT Public

Generation Interconnection Activity by Project Phase # In-Service ** # Signed Interconnect Agreement # Projects Cancelled *** # Completed Full Study # in Full Study # Screening Study Complete 350 # Initial Screening Study MW Capacity Under Study * MW In Commercial Operation ** * Nameplate capacity will change across time due to additional projects, cancellations, expirations, adjustments from study results, and projects being placed in service. 120,000 300 ** Having begun commercial operation since January 2006 100,000 250 *** Began tracking cancellations by month in March 2008 80,000 200 60,000 150 Project Count MW Capacity 100 40,000 50 20,000 0 0 Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07 Jul-07 Aug-07 Sep-07 Oct-07 Nov-07 Dec-07 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 19 ERCOT Public