Generation to be Dispatched(GTBD) Analysis

For the purpose of discussion only

PDCWG/QMWG Joint Meeting 11/02/2012

2

Discussion Points

1. Zonal/Nodal Regulation Deployment statistics

2. Regulation Deployment and Recall

3. Short-Term Load Forecast and Projected Load Ramp Rate (PLRR)

4. Analysis of Regulation Deployment (June 2012 to Aug 2012)

5. Discuss different GTBD calculation options including the one

proposed by NPRR 486

6. Statistical Analysis of different methods of calculating GTBD with

August and September data

7. Summary

04/21/23 For the purpose of discussion only

3

Zonal/Nodal Regulation Deployment Statistics

For the purpose of discussion only04/21/23

  Regulation-Up Deployed    (5 min sample data)

 Regulation-Down Deployed  (5 min sample data)

Regulation-Up Deployed    (hourly average data)

Regulation-Down Deployed    (hourly average data)

Zonal Operation (Jan to Nov. 2010)

357.250 -314.464 284.776 -234.374

Nodal Operation (Dec 2010 to Sept 2012

169.378 -138.174 124.176 -89.236

4

Regulation Deployment – Example 1

For the purpose of discussion only04/21/23

\\EDS_PI\ERCOT.JAGCTOT114.46

MW\\EDS_PI\ERCOT.FHZ59.998HZ

Regulation to Allocate ERCOT Frequency in AGC

17:58 17:57 17:56 17:54 17:53

10/30/2012 5:58:12 PMERCOT & QSE Summary

-80

-60

-40

-20

0

20

40

60

80

100

120

59.96

60.04

5

Regulation Deployment – Example 2

For the purpose of discussion only04/21/23

\\EDS_PI\ERCOT.JAGCTOT18.964MW\\EDS_PI\ERCOT.FHZ60.017HZ

Regulation to Allocate ERCOT Frequency in AGC

16:28 16:27 16:26 16:24 16:23

10/30/2012 4:28:12 PMERCOT & QSE Summary

-60

-40

-20

0

20

40

60

80

59.96

60.03

6

Short Term Load Forecast and PLRR

For the purpose of discussion only04/21/23

57296.89

57491.99

57685.70

57884.25

58025.39

58115.91

58326.0058379.52

58455.11

57459.71

57664.13

57861.63

58068.23

58223.11

58324.10

58535.1058581.54

58634.16

57000.00

57500.00

58000.00

58500.00

59000.00

13

:05

13

:10

13

:15

13

:20

13

:25

13

:30

13

:35

13

:40

13

:45

13

:50

MW 

STLF and Projected Load Ramp Rate 5 minute Ahead STLF 10 Min Ahead STLF

7

Analysis of Regulation Deployment

For the purpose of discussion only04/21/23

Regulation Analysis

Total Regulation-Up Duration

Total Regulation-Down Duration

Average Regulation-Up Deployed (MW)

Average Regulation-Down Deployed (MW)

June -12 52.44% 47.56% 177.51 -146.56

June-12 Peak Hour (14 to 18) 64.17% 35.83% 184.96 -118.37

July-12 53.23% 46.77% 150.89 -120.47

July - 12 Peak Hour (14 to 18) 69.19% 30.81% 160.68 -115.58

August-12 59.20% 40.80% 162.37 -116.85

August-12 Peak Hour (14 to 18) 75.99% 24.01% 174.47 -97.60

8

Analysis of Regulation Deployment……..continued

For the purpose of discussion only04/21/23

Regulation Analysis

Total Regulation-Up Duration

Total Regulation-Down Duration

Average Regulation-Up Deployed (MW)

Average Regulation-Down Deployed (MW)

September -12 53.99% 46.01% 169.90 -128.64

September-12 Peak Hour (14 to 18) 64.87% 35.13% 159.61 -119.00

October -12 47.47% 52.53% 138.36 -126.78

October - 12 Peak Hour (14 to 18) 48.74% 51.26% 129.90 -106.85

9

Underlying inputs for GTBD Calculation

1. Current GTBD Calculation

Total Gen + 1.1*5 *Projected Load Ramp Rate (PLRR)

2. GTBD1 (proposed per NPRR-486)

Total UDBP + Total Regulation Deployed + 1.1*5*PLRR

3. GTBD2 (modification includes using regulation-bias factor and modified K3)

Total Gen + 1.2*5*PLRR +0.1*Regulation Deployed

4. GTBD3 (increased K3)

Total Gen+1.3*5*PLRR

For the purpose of discussion only04/21/23

10

Statistical evaluation of GTBD calculation

For the purpose of discussion only04/21/23

Aug & Sept all hours

Current GTBD GTBD1 GTBD2 GTBD3

Mean 3.072 47.348 7.002 2.819

Standard Deviation

109.225 207.099 115.512 127.401

Zero mean probability

0.489 0.410 0.476 0.491

Aug & Sept (14-18 hours)

Current GTBD GTBD1 GTBD2 GTBD3

Mean 7.185 93.727 12.146 2.514

Standard Deviation

108.767 165.778 109.389 118.145

Zero mean probability

0.474 0.286 0.456 0.492

11

Statistical evaluation of GTBD calculation….(continued)

For the purpose of discussion only04/21/23

Aug & Sept (0-4 hours)

Current GTBD GTBD1 GTBD2 GTBD3

Mean -7.197 -27.471 -18.651 -27.040

Standard Deviation

91.378 178.913 95.113 98.297

Zero mean probability

0.531 0.561 0.578 0.608

Aug & Sept (5-8 hours)

Current GTBD GTBD1 GTBD2 GTBD3

Mean 7.261 29.773 26.545 38.180

Standard Deviation

114.002 201.453 119.175 126.917

Zero mean probability

0.475 0.441 0.412 0.382

12

Statistical evaluation of GTBD calculation….(continued)

For the purpose of discussion only04/21/23

Aug & Sept (09-13 hours)

Current GTBD GTBD1 GTBD2 GTBD3

Mean 26.642 115.954 59.668 77.240

Standard Deviation

112.424 217.447 110.020 116.149

Zero mean probability

0.406 0.297 0.294 0.253

Aug & Sept (19-23 hours)

Current GTBD GTBD1 GTBD2 GTBD3

Mean -17.739 21.112 -40.936 -69.951

Standard Deviation

113.653 230.697 116.169 123.142

Zero mean probability

0.562 0.464 0.638 0.715

13

Summary & Suggestions

1. Slide showing Regulation-Analysis reflects small bias toward usage of Regulation-Up Service for all durations

2. Regulation usage duration from 14:00 to 18:00 hours is greatly biased towards the usage of Regulation-Up service

3. Statistical Analysis of GTBD-Load (Error) reflects, the current GTBD error is very close to the probability of zero mean of the error (which is 0.5 for normal distribution)

4. Statistical Analysis shows that the GTBD calculation proposed through NPRR 486, increases Standard deviation of error, increase the mean of average error and reduces the probability of zero mean error away from 0.5 compared to all other options.

5. ERCOT Suggests that changes in the GTBD calculation be made as reflected in GTBD2 calculation. Regulation contribution to GTBD be tuned with the weighing factor . The Regulation contribution should be a rolling average value.

6. ERCOT believes that Step 5, “Regulation Recall based on pending base-point” functionality and some LFC tuning will help improve the regulation bias issue.

04/21/23 For the purpose of discussion only

14

Questions??

04/21/23 For the purpose of discussion only