06/04/2009TAC

2009 Long-term Demand and Energy Forecast (LTDEF) and Capacity, Demand and Reserves (CDR) Calculation

Dan WoodfinDirector, System Planning

TAC06/04/2009 2

LTDEF Models

• The Long-term Demand and Energy Forecast is based on a set of econometric models describing the hourly load in the region (by weather zone) as a function of certain economic and weather variables

• Economic and demographic data, including a county level forecast, are obtained on a monthly basis from Moody’s

• Forecast is based on “normal” weather

TAC06/04/2009 3

2009 LTDEF

Long-Term Hourly System Peak Demand Forecast (Base)

66,24767,641

68,96470,052

71,45472,672

73,90875,000

76,42077,591

78,766

56,086

60,03758,506

60,21462,188 67,395

69,39970,837

72,17273,369

74,87176,134

77,414

64,927

62,179

62,33963,491 64,056

65,494

50000

55000

60000

65000

70000

75000

80000

85000

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

Year

MW

Point Forecast 2008 Forecast 2008 Historical Point Forecast 2009 Forecast 2009

TAC06/04/2009 4

2009 LTDEF

Long-Term Energy Forecast

281 285 289 299 306 308 312 315 322 333 342 349 356 363 370 376 382

312

319 326 333 339 345 350 356 363 369 375 380

314

0

50

100

150

200

250

300

350

400

450

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Year

TW

h

Historical Actual 2008 Forecast 2009

Forecast 2008 2008 Forecast for 2008 Frcst Trend 2009

TAC06/04/2009 5

Example Economic Drivers used in 2009 LTDEF

22,500

23,500

24,500

25,500

26,500

27,500

28,500

29,500

30,500

31,500

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Year

$ p

er P

erso

n

Forecasted 2008 Forecasted 2009

21,400

22,400

23,400

24,400

25,400

26,400

27,400

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Year

Nu

mb

er

of

Pe

rso

ns

(0

00

's)

Forecasted 2008 Forecasted 2009

800,000

850,000

900,000

950,000

1,000,000

1,050,000

1,100,000

1,150,000

1,200,000

1,250,000

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Year

Mil.

Co

ns

tan

t $

Forecasted 2008 Forecasted 2009

9,200

9,700

10,200

10,700

11,200

11,700

12,200

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Year

Nu

mb

er

of

Pe

rso

ns

(0

00

's)

Forecasted 2008 Forecasted 2009

Total Non-Farm Employment Gross Domestic Product

PopulationReal Personal Per-Capita Income

TAC06/04/2009 6

CDR Summary

Load Forecast: 2009 2010 2011 2012 2013 2014Total Summer Peak Demand, MW 63,491 64,056 65,494 67,394 69,399 70,837 less LAARs Serving as Responsive Reserve, MW 1,115 1,115 1,115 1,115 1,115 1,115 less LAARs Serving as Non-Spinning Reserve, MW 0 0 0 0 0 0 less BULs, MW 0 0 0 0 0 0 less Energy Efficiency Programs (per HB3693) 110 242 242 242 242 242Firm Load Forecast, MW 62,266 62,699 64,137 66,037 68,042 69,480

Resources: 2009 2010 2011 2012 2013 2014Installed Capacity, MW 63,492 61,800 61,800 61,800 61,800 61,800Capacity from Private Networks, MW 5,313 5,318 5,318 5,318 5,318 5,318Effective Load-Carrying Capability (ELCC) of Wind Generation, MW 708 708 708 708 708 708RMR Units to be under Contract, MW 115 0 0 0 0 0Operational Generation, MW 69,628 67,826 67,826 67,826 67,826 67,826

50% of Non-Synchronous Ties, MW 553 553 553 553 553 553Switchable Units, MW 2,848 2,848 2,848 2,848 2,848 2,848Available Mothballed Generation , MW 0 401 479 479 479 479Planned Units (not wind) with Signed IA and Air Permit, MW 0 3,769 4,389 5,414 7,206 7,206ELCC of Planned Wind Units with Signed IA, MW 0 76 121 168 211 211Total Resources, MW 73,029 75,472 76,215 77,287 79,122 79,122

less Switchable Units Unavailable to ERCOT, MW 317 158 0 0 0 0less Retiring Units, MW 0 0 0 0 0 0Resources, MW 72,712 75,314 76,215 77,287 79,122 79,122

Reserve Margin 16.8% 20.1% 18.8% 17.0% 16.3% 13.9%(Resources - Firm Load Forecast)/Firm Load Forecast

TAC06/04/2009 7

GATF?

• Some need to revise rules for CDR calculation based on new technology types and changed conditions

• ERCOT will undertake new Loss of Load Probability (LOLP) study later this year– Used to set reserve margin target minimum– Used to set effective load-carrying capability (ELCC) of wind

• Suggest waiting to resurrect GATF until late 2009– Allow simultaneous consideration of LOLP study and any other

CDR changes– Provide recommendation in time for April 2010 NERC Summer

Assessment submission and May 2010 ERCOT CDR

Questions?