Generation Adequacy Task Generation Adequacy Task Force Update to WMSForce Update to WMS

November 18, 2009November 18, 2009

GATF has met 3 times: Sept. 22, Oct. 13, and Nov. 3, GATF has met 3 times: Sept. 22, Oct. 13, and Nov. 3, 20092009Next meeting set for December 1Next meeting set for December 1stst..GATF Charter and Goals Developed and included in last GATF Charter and Goals Developed and included in last month’s update:month’s update:– Highlights of goals: Highlights of goals:

Review all the findings and recommendations from the previous Review all the findings and recommendations from the previous GATF reports.GATF reports.Thorough review of CDRThorough review of CDRRecommendation for EILSRecommendation for EILSRecommendations for new technologies (solar, storage, etc.)Recommendations for new technologies (solar, storage, etc.)Recommendation for new LOLP (target reserve margin) study (GATF Recommendation for new LOLP (target reserve margin) study (GATF input into assumptions, data sources, results, etc.).input into assumptions, data sources, results, etc.).Complete a draft report by the December 2009 WMS meeting that Complete a draft report by the December 2009 WMS meeting that provides ERCOT planning with recommendations on all the provides ERCOT planning with recommendations on all the assumptions to use in the target reserve (LOLP) study and assumptions to use in the target reserve (LOLP) study and subsequent reserve margin calculations.subsequent reserve margin calculations.Complete a final report for consideration and vote at the January Complete a final report for consideration and vote at the January 2010 TAC meeting 2010 TAC meeting

Wind Historical Data Provided by Luminant:Wind Historical Data Provided by Luminant:

Meeting Updates Meeting Updates

CDR: Thorough review will occur on December 3CDR: Thorough review will occur on December 3rdrd..– Is 5 year horizon adequate?Is 5 year horizon adequate?– Does it need high and low forecasts?Does it need high and low forecasts?– Flow diagram of processesFlow diagram of processes– Why is county data needed?Why is county data needed?EILS methodology is still under developmentEILS methodology is still under developmentLOLP Study (Target Reserve Margin) DiscussionLOLP Study (Target Reserve Margin) Discussion

– Inputs and assumptions were reviewed at Nov. 3Inputs and assumptions were reviewed at Nov. 3rdrd meeting. meeting. What will be the source of information for generation forced outage rate What will be the source of information for generation forced outage rate assumptions?assumptions?What years will be studied?What years will be studied?Will transmission topology be modeled? If so, to what level of detail?Will transmission topology be modeled? If so, to what level of detail?What assumptions will be used for scheduled maintenance of resources?What assumptions will be used for scheduled maintenance of resources?What type of generation technology should be utilized when estimating the What type of generation technology should be utilized when estimating the effective load carrying capability (ELCC) of wind resources?effective load carrying capability (ELCC) of wind resources?What resource technology types should be added to the study when What resource technology types should be added to the study when determining reserve margins?determining reserve margins?What modifications, if any, should be made to the model’s input What modifications, if any, should be made to the model’s input assumptions regarding wind resources? Should wind be modeled with assumptions regarding wind resources? Should wind be modeled with different ELCCs based on their geographic location (west, coastal, etc.)? different ELCCs based on their geographic location (west, coastal, etc.)? What assumptions should be made for other renewable technologies (solar, What assumptions should be made for other renewable technologies (solar, biomass, etc.)? What is the source of information for generation forced biomass, etc.)? What is the source of information for generation forced outage rate assumptions? outage rate assumptions?

Synopsis of Discussions and IssuesSynopsis of Discussions and Issues

Luminant provided an overview of wind Luminant provided an overview of wind historical datahistorical data

– Indicated current 8.7% level in CDR may be Indicated current 8.7% level in CDR may be too low.too low.

– ERCOT staff believes their studies will also ERCOT staff believes their studies will also indicate an increase in the ELCC for wind, indicate an increase in the ELCC for wind, primarily due to the increased wind generator primarily due to the increased wind generator quantities and more geographic diversity quantities and more geographic diversity among wind farms today among wind farms today

Synopsis of Discussions and IssuesSynopsis of Discussions and Issues

Wind DataSupplied by Luminant

Installed Wind Capacity at Peak Hour

-

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

2006 2007 2008 2009

MW

June

July

August

September

Wind DataSupplied by Luminant

All Hours (June-Sept.)

26.8%27.5%

19.4%

26.6%

25.1%24.2%

15.1%

30.9%

24.8%

23.8%

41.0%

26.4%

13.4%

14.8%

23.9%

18.3%

22.9%

21.1%

25.6%

22.0%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

June July August September Annual Avg.*

% In

stal

led

Win

d C

apac

ity

2006

2007

2008

2009

Wind DataSupplied by Luminant

Peak Hours (HE 1600 - HE 1900)

16.5%

17.9%

13.6%

19.2%

16.8%16.6%

12.2%

22.2%

14.8%

16.5%

33.5%

21.3%

9.7%9.1%

18.4%

21.3%

14.9%

16.9%16.1%

17.3%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

June July August September Annual Avg.*

% In

stal

led

Win

d C

apac

ity

2006

2007

2008

2009

Wind DataSupplied by Luminant

Monthly Peak Load Hour

2.1%

4.7%

17.1%

7.7% 7.9%

22.3%

14.6%

3.9%

13.2% 13.5%

43.9%

0.9%

11.5%

19.3% 18.9%

3.5%

20.3%

7.3%

5.2%

9.1%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

50.0%

June July August September Annual Avg.*

% In

stal

led

Win

d C

apac

ity

2006

2007

2008

2009

Wind DataSupplied by Luminant

System Peak Hour

17.1%

3.9%

11.5%

20.3%

13.2%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

2006 2007 2008 2009 Average

% In

stal

led

Win

d C

apac

ity

Impact of Revised ELCC on Reserve Margins Supplied by Luminant

Year 10% ELCC 12% ELCC 15% ELCC2009 106 268 513 2010 117 297 567 2011 124 315 600 2012 131 332 634 2013 137 348 665 2014 137 348 665

Year 10% ELCC 12% ELCC 15% ELCC2009 0.2% 0.4% 0.8%2010 0.2% 0.5% 0.9%2011 0.2% 0.5% 0.9%2012 0.2% 0.5% 1.0%2013 0.2% 0.5% 1.0%2014 0.2% 0.5% 1.0%

*Based on May 2009 ERCOT CDR

Change in Wind Capacity Value (MW)

Change in Reserve Margin*

Questions or Comments?Questions or Comments?