future ancillary service team (fast) and technical advisory committee (tac) workshop #2
DESCRIPTION
Future Ancillary Service Team (FAST) and Technical Advisory Committee (TAC) Workshop #2 ERCOT Staff August 25, 2014. Outline. Recap and Overview of Schedule Review How AS Requirements are Determined Review Options on When Quantities are Finalized and Provided to the Market - PowerPoint PPT PresentationTRANSCRIPT
Future Ancillary Service Team (FAST) and Technical Advisory Committee
(TAC) Workshop #2
ERCOT Staff
August 25, 2014
1
• Recap and Overview of Schedule
• Review How AS Requirements are Determined
• Review Options on When Quantities are Finalized and Provided to the Market
• Discuss Specific Policy Cuts
• Update on RFP for CBA
• Review Synchronous Inertial Response (SIR)
• Next Steps
Outline
2
1. Develop Request for Proposals (RFP) for Cost Benefit Analysis (CBA) 2. Specific Policy Questions and items to include in the base-line 8/15/14
3. FAST/TAC Workshop 8/25/14
4. TAC meeting 8/28/14 (policy cuts)
5. Comments on draft NPRR due to ERCOT 10/1/14
6. Post revised NPRR 11/1/14
7. CBA initiated on revised NPRR 11/1/14
From July 31 TAC Meeting
3
Summary of Proposed Future Ancillary Services
Regulation Up
Fast-Responding Regulation Up
Current Proposed
Fast Frequency Response 1
Primary Frequency Response
Contingency Reserves 1
Synchronous Inertial Response
Supplemental Reserves 1
Mostly unchanged
59.8 Hz, Limited duration
59.7 Hz, Longer durationFast Frequency Response 2
Contingency Reserves 2
SCED-dispatched
Manually dispatched
Supplemental Reserves 2
SCED-dispatched
Manually dispatched
Ongoing development
Non-Spin
Responsive
Regulation Down
Fast-Responding Regulation Down
Regulation Up
Fast-Responding Regulation Up
Regulation Down
Fast-Responding Regulation Down
4
Determining AS Quantities
AS Framework
AS Framework
Technical Studies
Technical Studies
Regulatory Reqs
Regulatory Reqs
AS Methodology
AS Methodology
Expected Operating Conditions
Expected Operating Conditions
Hourly AS QuantitiesHourly AS Quantities
Technical AS ReqsTechnical AS Reqs
•Defines AS Products,
settlements, perf.
Reqs, etc
•Implemented in NPRR
•Defines AS Products,
settlements, perf.
Reqs, etc
•Implemented in NPRR
•Studies of S
ystem
perform
ance under diffe
rent
conditions
•Updated as needed
•Studies of S
ystem
perform
ance under diffe
rent
conditions
•Updated as needed
•e.g. N
ERC BAL-003-1
standard•
e.g. NERC BAL-003-1
standard
• Defines AS requirements
as a function of operating
conditions
• Updated when studies or
regulatory requirements are
updated
• Defines AS requirements
as a function of operating
conditions
• Updated when studies or
regulatory requirements are
updated • Documents AS
technical requirements
• Defines how operating
conditions will b
e used
to determine
procurement quantities
• Updated Annually
• Documents AS
technical requirements
• Defines how operating
conditions will b
e used
to determine
procurement quantities
• Updated Annually
•Determ
ined at
lead time(s)
defined in AS
Methodology•Determ
ined at
lead time(s)
defined in AS
Methodology
5
Determining AS Quantities
AS Framework
AS Framework
Technical Studies
Technical Studies
Regulatory Reqs
Regulatory Reqs
AS Methodology
AS Methodology
Expected Operating Conditions
Expected Operating Conditions
Hourly AS QuantitiesHourly AS Quantities
Technical AS ReqsTechnical AS Reqs
6
Study results and proposed methods to determine AS
Requirements
PFRS and FFRSCriteria : Frequency nadir shall be equal to
or above 59.4 Hz for loss of two largest units. (0.1 Hz margin for the first stage of UFLS at 59.3 Hz)
No angular and voltage instabilityWill include
Minimum amount of PFRS Minimum amount of PFRS and FFRS Equivalency ratio between PFR and FFR
High Frequency Over-shoot
8
Minimum Amount of PFR:BAL-003-1: The ERCOT Interconnection Frequency
Response Obligation (IFRO) is currently 413MW/0.1 HzNo FFR Response is expected for 0.3 Hz band
between 60 Hz and 59.70 Hz assuming no FFR1 participation
PFR(min) = 413 MW/0.1 Hz * 3 (since FFR does not respond up to 0.3 Hz deviation) = 1,239 MW
Stability analysis is used to determineMinimum Amount of PFRS and FFRSInterdependence ratio between PFR and FFRMinimum PFR can be changed based on annual review
of IFRO by NERC
PFRS and FFRS (Continued)
9
Numerous frequency stability runs were conducted on multiple scenarios.
Key Assumption:No wind dynamic modelsLoad Resources responded within 30 cyclesGovernor response modeled only for Resources
assigned PFRS in the simulation of a low frequency event 30% PFRS are provided by Coal units 70% PFRS are provided by NG units
Minimum Amount of PFRS and FFRS
10
FFR1(59.8 Hz) Vs FFR2(59.7 Hz)
PFR (MW)Equivalency Ratio(FFR2 v.s. FFR1)
1000 1.06
1400 1.07
1800 1.09
2200 1.11
2600 1.08
1 MW FFR1 ≈ 1 MW FFR2
Test: Twelve Study Cases
15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65
250
300
350
400
450
500
550
600
650
700
Netload Level (GW)
Ine
rtia
(G
W*s
)
Inertia v.s. Netload (June, 2013 - May, 2014)
case1
case2case3
case4
case5
case6
case7
case8
case9
case10
case11
case12
Inertia=2*Kinetic Energy=2*H*MVA
12
An Example of Case StudyMinimum amount of FFR and PFR is determined by preventing frequency from dropping below 59.4Hz for loss of 2 largest units (2750MW)
Preliminary FFR and PFR Study ResultsCase
1Case
2Case
3Case
4Case
5Case
6Case
7Case
8Case
9Case
10Case
11Case
12
FFR/PFR 2.2:1 2.0:1 1.5:1 1.4:1 1.3:11.25:
11.13 :
11.08:
11:1 1.0:1 1:1 1:1
Net load Level(GW)
15-20 15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 60-65
Inertia (GW∙s) 239 271 304 354 403 459 511 556 593 631 664 700
PFR needed(no FFR)
5200 4700 3750 3370 3100 3040 2640 2640 2240 2280 2140 2140
Case1
Case2
Case3
Case4
Case5
Case6
Case7
Case8
Case9
Case10
Case11
Case12
FFR/PFR 2.2:1 2.0:1 1.5:1 1.4:1 1.3:11.25:
11.13 :
11.08:
11:1 1:1 1:1 1:1
PFR Min 1240 1240 1240 1240 1240 1240 1240 1240 1240 1240 1240 1240
FFR needed with PFR Min
1800 1696 1641 1511 1431 1440 1239 1296 1000 1040 900 900
Combined Total 3040 2936 2881 2751 2671 2680 2479 2536 2240 2280 2140 2140
14
PFR vs FFR (59.7Hz) Result Summary
Case1 Case2 Case3 Case4 Case5 Case6 Case7 Case8 Case9 Case10 Case11 Case12
FFR/PFREquivalence
Ratio2.2:1 2.0:1 1.5:1 1.4:1 1.3:1 1.25:1 1.13 :1 1.08:1 1:1 1:1 1:1 1:1
Net load (GW) 15-20 15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 60-65
Inertia(GW s)∙ 239 271 304 354 403 459 511 556 593 631 664 700
Conclusion:As system inertia increases, FFR/PFR ratio gradually decreases to about 1 where PFR and FFR are approximately same in terms of arresting system frequency
Conclusion:As system inertia increases, FFR/PFR ratio gradually decreases to about 1 where PFR and FFR are approximately same in terms of arresting system frequency
15
Maximum of : – 98.8 percentile of the five minutes net load change
and deployment during the 30 days period to the time of the study.
– 98.8 percentile of the five minutes net load change for the same month of the previous year
– Additional adjustment based on CPS1 score for each hour
REG-UP and REG-DOWN
16
Contingency Reserve Service (CRS) Recover frequency from settling point to 60
Hz Build in a margin based on the amount of
CRS a single Resource can provide CRS need will be dynamic based on system
conditions just like PFRS and FFRS requirement
17
95 Percentile 6-Hour-ahead net-load forecast error
SRS for any 4-hour block is equal to 95 percentile of 6-hour ahead net load forecast error less Reg-Up, Contingency Reserve and portion of combined PFRS/FFRS
For extreme weather condition, SRS requirement to be based on unit forced outage rate
Supplemental Reserve
18
This is open to discussion
This is open to discussion
Determining AS Quantities
AS Framework
AS Framework
Technical Studies
Technical Studies
Regulatory Reqs
Regulatory Reqs
AS Methodology
AS Methodology
Expected Operating Conditions
Expected Operating Conditions
Hourly AS QuantitiesHourly AS Quantities
Technical AS ReqsTechnical AS Reqs
19
Efficiency versus Certainty in Setting AS Quantities
Efficiency versus Certainty
• Max Certainty:– A fixed amount of a particular service could be procured for every
hour based on the amount needed to cover worst case conditions– This would result in too much being procured for most hours
• Max Efficiency:– The amount to be procured for each hour of the next day could be
set prior to the DA market, based on expected conditions for that next day
– This would make it difficult to hedge requirements
• Need to determine an appropriate tradeoff– May vary by service
21
Options for PFRS/FFRS Procurement
1. ERCOT is offering five different options for procurement of PFRS and FFRS
2. The options differ based on how early market prefers to know the minimum quantities
3. Day-Ahead adjustment proposed is consistent with current protocol language and ERCOT does not anticipate performing the day-ahead adjustment routinely Day-Ahead analysis look at projected net load
conditions and unit commitmentsPlease note : The Options discussed for PFRS and FFRS
can be tailored for all AS products
22
Options for procurement of PFRS and FFRS
DA MA YA
Option 1 √
Option 2 √
Option 3 ∆ √
Option 4 ∆ ∆ √
Option 5 ∆ √
DA: Day-Ahead, MA: Month-Ahead, YA: Year Ahead√: Determine the needs for the entire period∆: Determine the “incremental” needs based on the system condition
23
Option I for PFRS and FFRS Requirements
Determine a number based on the study performed to simulate extreme condition and procure that amount for all hours
24
Proposed Options for PFRS/FFRS Requirements
Option IIPublish the minimum PFRS and FFRS
requirement and FFR to PFR equivalence ratio by 6am for the next operating day
Posting will include minimum requirements for each hour of the operating day
25
Option II for PFRS and FFRS Requirements
Time
AS
Req
uire
men
t
• Publish the requirement in Day-Ahead.
• Publish the requirement in Day-Ahead.
Real Time Needs
Day-Ahead
26
Proposed Options for PFRS/FFRS Requirements
Option IIIPublish the 80% of calculated minimum PFRS and
FFRS requirement, and FFR to PFR equivalence ratio by 20th of each month for the upcoming month
Make any necessary Day-Ahead adjustment and post the adjustments by 6 am for the next operating day
Monthly and Day-Ahead posting to MIS will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day
This percentage is open to discussion
27
Options III for PFRS and FFRS Requirements
Time
AS
Req
uire
men
t
• Publish the requirement using 80% of the need Month-Ahead
• Day-Ahead : determine incremental need
• Publish the requirement using 80% of the need Month-Ahead
• Day-Ahead : determine incremental need
Real Time Needs
80% of Month-Ahead Day-Ahead
28
Proposed Options for PFRS/FFRS Requirements
Option IVPublish 80% of calculated minimum PFRS and FFRS
requirement, and FFRS to PFRS equivalency ratio by December 1st, for each month of upcoming year
Perform monthly adjustments if needed and post it to MIS by 20th of each month for the upcoming month
Perform day-ahead adjustments and post it to MIS by 6 am for the next operating day
Annual, Monthly and Day-Ahead posting will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day
This percentage is open to discussion
29
Options IV for PFRS and FFRS Requirements
Time
AS
Req
uire
men
t
Real Time Needs
80% of Year-Ahead Month-Ahead
Day-Ahead
• Publish the requirement using 80% of the need Month-Ahead
• Month-Ahead/Day-Ahead : determine incremental need
• Publish the requirement using 80% of the need Month-Ahead
• Month-Ahead/Day-Ahead : determine incremental need
30
Proposed Options for PFRS/FFRS Requirements
Option VPublish 80% of calculated minimum PFRS
and FFRS requirement, and FFRS to PFRS equivalency ratio by December 1st, for each month of upcoming year
Perform day-ahead adjustments and post it to MIS by 6 am for the next operating day
Annual and Day-Ahead posting will include requirements and equivalency ratio between FFRS and PFRS, for each 4-hour block of the operating day
This percentage is open to discussion
31
Options V for PFRS and FFRS Requirements
Time
AS
Req
uire
men
t
• Publish the requirement using 80% of the need annually
• Day-Ahead : determine incremental need
• Publish the requirement using 80% of the need annually
• Day-Ahead : determine incremental need
Real Time Needs
80% of Year-Ahead Day-Ahead
32
Similar to PFRS and FFRS, Regulation , CRS and SRS requirements can be published day-ahead, monthly or annually
Other Services
33
Policy Decisions
Luminant ERCOT Steel Companies Energy Storage Association Co-operative Segment
Summarize Specific Policy Cuts for TAC consideration at the 8-28-14 TAC meeting
Discuss Specific Policy Cuts
35
Cost/Benefit Assessment Status
• Met with Segment Representatives on 8-20-14 and discussed the draft “High Level Description of the Cost Benefit Analysis of the Future Ancillary Service Framework”
• ERCOT to revise the document and include more language on deliverables expected from the Contractor.
• Plan to send out revised document to the group for their review after the 8-28-14 TAC meeting.
• The new target is to send out the RFP soon after the 8-28-14 TAC meeting
• Draft timeline indicates that a Contractor could possibly start in November and the final report and presentations could possibly be expected in February
Update on RFP for CBA
37
Synchronous Inertia Response Service
SIR is stored kinetic energy that is extracted from the rotating mass of synchronous machines following a disturbance in a power system
SIR is not included in the proposed future AS framework and the draft NPRR.
Synchronous Inertial Response
39
SIR can be provided by synchronous machines, whenever in operation.
Quantity of inertia contribution is determined as kinetic energy that can be provided by a synchronous machine during system imbalance:
2·H·MVA
where H is machine inertia constant in seconds, MVA is machine’s rated power
SIR is based on actual physical characteristics of a machine SIR is independent of machine’s operating point.
Synchronous Inertial Response
40
Maintain minimum Rate of Change of Frequency (RoCoF) Provide sufficient time from Point A to Point C, for the Ancillary
Services to respond. With increasing use of non-synchronous generation, changing load
characteristics, increase in Combined Cycle units (lower inertia), the system SIR is reduced.
As a result, RoCoF increases, leaving less time for primary frequency response to deploy and arrest the system frequency excursion.
SIR Need
41
42
SIR, Current Conditions
Case TimeGeneration
(MW)Load (MW)
WIND (MW)
Wind Penetration
Ratio
Inertia(GW-Sec)
A3/31/2014
2:00 24,822 24,534 9,514 0.39 266
B3/26/2014
20:00 36,423 35,827 10,120 0.28 354
C4/19/2014
2:00 24,313 24,822 6,822 0.27 260
Case A: Highest Wind Penetration CaseCase B: Highest Wind MW CaseCase C: Lowest Inertia Case
Synchronous Inertia (June 2013 - May 2014)
15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65
250
300
350
400
450
500
550
600
650
700
Netload Level (GW)
Ine
rtia
(G
W*s
)
Inertia v.s. Netload (June, 2013 - May, 2014)
Inertia=2*Kinetic Energy=2*H*MVA
43
To date, RoCoF at HWLL conditions during frequency events is around 0.2 Hz/s and the average time to reach frequency nadir is 4-6 seconds.
Analysis based on Jan-May 2014 system conditions indicated RoCoF of 0.65 Hz/s for two largest unit trip
SIR available under current operating conditions is still sufficient. SIR will not be introduced as a new AS yet. ERCOT started to monitor SIR in real-time since July 2014. ERCOT will continue to analyze the need of SIR and value of
emulated inertia* response from non-synchronous generation resources.
* Emulated Inertia Response is super-fast (20ms), short duration (8 - 20 s) active power injection in response to frequency decrease below pre-set threshold
SIR, Summary and Future Work
44
• ERCOT in collaboration with EPRI is conducting studies to verify value of wind generation resources providing EIR and/or PFR and associated uncertainty in the day ahead
• Two types of studies:
− Dynamic studies:
− EIR&PFR uncertainty: comparing Day Ahead wind power production forecast vs actual wind power production, DA wind turbine availability vs Real Time turbine availability and how that impacts EIR and/or PFR that wind generation resources can offer in the DA and deliver in RT.
• The results of these studies are expected by the end of this year
Case Study: EIR & PFR from Wind Generation Resources
45
WGRs do not provide AS
WGRs provide EIR
WGRs provide PFR
WGR provide EIR&PFR
HWLL √ √ √ √MWML √ √ √ √LWHL √ √ √ √