review of system alerts
DESCRIPTION
Review of System Alerts. Transmission Workgroup 11 th October 2011. Agenda. Introductions Actions from Last meeting Day ahead Within Day Information GBA Next Steps Firm Monitor. Review of the Gas Balancing Alert arrangements. Transmission Workgroup 11 th October 2011. Background. - PowerPoint PPT PresentationTRANSCRIPT
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Review of System Alerts
Transmission Workgroup 11th October 2011
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2
Agenda
1. Introductions
2. Actions from Last meeting
3. Day ahead
4. Within Day
5. Information
6. GBA Next Steps
7. Firm Monitor
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Review of the Gas Balancing Alert arrangements
Transmission Workgroup 11th October 2011
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4
Background
GBA has been in place for 5 years
The GBA sought to provide a signal to the Industry that a significant end of
day NTS system imbalance is forecast.
GBA principally implemented to provide the industry with a signal for demand
side response, where a significant gas flow deficit was forecasted either day
ahead or within day.
Recent user feedback indicates that some aspects of the GBA signal may no
longer be as effective as when initially introduced.
Timely review fits with SCR focus on Gas Deficit Emergency arrangements.
Intent of review is to focus is on preventative measures, alerting the market to
respond.
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5
What Is a Gas Balancing Alert (GBA)
A GBA has two triggers, day ahead (no discretion) or within day (discretion)
Or
Expectation on the market to respond by increasing supply or initiating a demand side reduction.
National Grid have a UNC obligation (V 5.9) to alert system users to a EOD supply/demand imbalance via a Gas Balancing Alert (GBA)
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Day ahead
Transmission Workgroup 11th October 2011
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Day ahead
National Grid perceived areas for review:
Refining prevailing UNC GBA provisions;
Renaming and splitting of the reference ‘GBA’ to separately defined within day and day ahead signals;
Aligning UNC with the calculation methodology undertaken by National Grid NTS during the GBA;
Introducing the ability for National Grid NTS to recall a GBA notice.
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The UNC definition for the day ahead GBA process implies that National Grid is forecasting total system supplies for the coming gas.
The current methodology is a view of total system supplies for the winter period, which is reviewed monthly.
Supply patterns are too volatile to accurately forecast day ahead.
Issues with the Day Ahead GBA Trigger Level Methodology
NSS Winter 2010/11
0
50
100
150
200
250
300
350
400
450
01/1
0/20
10
08/1
0/20
10
15/1
0/20
10
22/1
0/20
10
29/1
0/20
10
05/1
1/20
10
12/1
1/20
10
19/1
1/20
10
26/1
1/20
10
03/1
2/20
10
10/1
2/20
10
17/1
2/20
10
24/1
2/20
10
31/1
2/20
10
07/0
1/20
11
14/0
1/20
11
21/0
1/20
11
28/0
1/20
11
04/0
2/20
11
11/0
2/20
11
18/0
2/20
11
25/0
2/20
11
04/0
3/20
11
11/0
3/20
11
18/0
3/20
11
25/0
3/20
11
-80-70-60-50-40-30-20-100102030405060
Actual NSS NSS Change (Right Axis) Trigger Level NSS
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Day Ahead GBA Trigger Level Methodology
What should this include:
NSS calculation
LNG assumption
Beach
Norway
Interconnector
Storage assumption
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LNG assumptions
200
250
300
350
400
450
500
550
01/1
0/20
10
08/1
0/20
10
15/1
0/20
10
22/1
0/20
10
29/1
0/20
10
05/1
1/20
10
12/1
1/20
10
19/1
1/20
10
26/1
1/20
10
03/1
2/20
10
10/1
2/20
10
17/1
2/20
10
24/1
2/20
10
31/1
2/20
10
07/0
1/20
11
14/0
1/20
11
21/0
1/20
11
28/0
1/20
11
04/0
2/20
11
11/0
2/20
11
18/0
2/20
11
25/0
2/20
11
04/0
3/20
11
11/0
3/20
11
18/0
3/20
11
25/0
3/20
11
GBA Winter 10/11 GBA (LNG @ D2) D-1 13:00 Demand Forecast D-1 GBA
16 D-1 GBA's
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Day Ahead Notification
Issues to be addressed in respect of specific GBA type :
Day Ahead GBA;
rename to a ‘notification’;
aligning UNC with the NSS calculation methodology undertaken by National Grid NTS;
ability for National Grid NTS to recall notification.
Any comments or additions?
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Within Day GBA
Transmission Workgroup 11th October 2011
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The within Day GBA is triggered by an incident that will reduce supplies by 25mcm/d for the remainder of the gas day leading to an EOD supply demand imbalance
National Grid has discretion on within day GBA’s
Expectation on the market to balance EOD position (supply/Demand side response to GBA)
Within Day GBA
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National Grid perceived areas for review:
Refining prevailing UNC GBA provisions;
No ability to withdraw a GBA;
Methodology constrains issuing of GBA. Consider reviewing methodology;
No ability to signal a within day issue (physical linepack issue) potential GDE.
Within Day GBA issues
Additional issue identified from industry:
- Change of name from an ‘alert’
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Within Day GBA
Issues to be addressed in respect of specific GBA type :
Within Day GBA;
Consider changing methodology;
Consider renaming;
Provide ability for National Grid NTS to recall a GBA notice.
Any comments or additions?
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Within Day Imbalance
Transmission Workgroup 11th October 2011
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Change in Daily Linepack
Pre
ssur
e /
Line
pack
Time
Max Daily Pressure
Min Daily Pressure
06:00 06:00
Change in daily linepack
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Within-Day Linepack VarianceWithin day max-min range of NTS linepack (mcm)
0
2
4
6
8
10
12
14
16
18
20
Apr
-01
Aug
-01
Dec
-01
Apr
-02
Aug
-02
Dec
-02
Apr
-03
Aug
-03
Dec
-03
Apr
-04
Aug
-04
Dec
-04
Apr
-05
Aug
-05
Dec
-05
Apr
-06
Aug
-06
Dec
-06
Apr
-07
Aug
-07
Dec
-07
Apr
-08
Aug
-08
Dec
-08
Apr
-09
Aug
-09
Dec
-09
Apr
-10
Aug
-10
Dec
-10
Apr
-11
Aug
-11
In d
ay r
an
ge
of
linep
ack
(mcm
)
Rolling 30 day average
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Yearly Profile Comparison
Comparison of within day max-min range of NTS linepack (mcm)
0
2
4
6
8
10
12
14
16
18
20
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
In d
ay r
ange
of
linep
ack
(mcm
) .
Rolling 30 day average swing 2001/2 Rolling 30 day average swing 2010/11
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Increase of Occurrence
Occurences of in-day linepack range above 14 mcm
0
5
10
15
20
25
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Nu
mb
er o
f O
ccu
rren
ces
2006 2007 2008 2009 2010 2011
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Within Day Imbalance
Issues to be addressed in respect of specific GBA type:
Within Day Imbalance;
Inform the market of the issue;
National Grid take actions to resolve the issue.
Any industry concerns with proposed approach?
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Additional Information
Transmission Workgroup 11th October 2011
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Information aim
Improve understanding and monitoring of extent of system issue and how the market is responding;
National Grid NTS – consider what information would help the market to initiate timely response;
Industry information – consider what information would aid system operation in times of high system stress.
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Information Provision
Potential areas for improved information from the SO:
Day ahead GBA message to include volume above trigger level: e.g. GBA for 29 December - 7mcm above the trigger level
Breakdown of NSS assumption
Narrative on rationale for any within winter changes in NSS
Notification of within day system critical issue e.g. time of system issue is 18:30 (or GBA issued for period 15:00 – 22:00). Should this be linked to the GBA?
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Nomination imbalance
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26
Notes on graphs
In addition to Actual linepack and PCLP, linepack graphs show the total net shipper nomination imbalance, the variation of PCLP from the opening linepack figure and a variation of PCLP from the opening which is adjusted to account for variations in demand (i.e. closer to the DFN impact on PCLP)
The shipper nomination graphs show positive and negative imbalances but only include figures for shippers with an imbalance greater than 1 mcm at 06:00 on the day in question.
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8th August 2011
Shipper positive nomination imbalances 8th August 2011 (imbalances >1 mcm at 06:00)
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00Im
bal
ance
(m
cm)
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8th August 2011
Shipper negative nomination imbalances 8th August 2011 (imbalances >1 mcm at 06:00)
-80.0
-70.0
-60.0
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
20.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce (
mcm
)
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29
8th August 2011High Actual linepack swing (16mcm) – notable as during summer
Low opening PCLP (318.5) driven by low opening shipper nominations
Linepack 8th August 2011
305.0
310.0
315.0
320.0
325.0
330.0
335.0
340.0
345.0
350.0
355.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
Lin
epac
k (m
cm
)
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
PC
LP
dev
iati
on
an
d N
om
ina
tio
n im
bal
an
ce (
mcm
)
DFN PCLP Actual National Linepack
PCLP deviation from opening Net nomination imbalance
Demand adjusted PCLP deviation from opening
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20th December 2010
Shipper negative nomination imbalances 20th December 2011 (imbalances >1 mcm at 06:00)
-40.0
-35.0
-30.0
-25.0
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce
(mcm
)
D-1 GBA issued 16:58
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31
20th December 2010
Shipper positive nomination imbalances 20th December 2010 (imbalances >1 mcm at 06:00)
-20.0
0.0
20.0
40.0
60.0
80.0
100.0
120.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce
(mcm
)
D-1 GBA issued 16:58
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32
20th December 2010Relatively High Actual linepack swing (18.6mcm)
D-1 GBA issued for following day at 18:25
Linepack 20th December 2011
330
335
340
345
350
355
360
365
370
375
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
Lin
epac
k (
mcm
)
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
PC
LP
dev
iati
on
an
d N
om
inat
ion
im
bal
ance
(m
cm)
DFN PCLP Actual National LinepackPCLP deviation from opening Net nomination imbalanceDemand adjusted PCLP deviation from opening
D-1 GBA issued 16:58
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33
Observations
On the 8th the imbalance was entirely corrected by the market, without direct intervention from National Grid.
On the 20th, on the day we of issued a Day Ahead GBA, there appears to be a move towards balance in shipper nominations coincident with the issue of the GBA, even though the GBA relates to the following gas day.
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18th August 2011High Actual linepack swing (25.5mcm) – particularly notable as during summer but also in top 10 of last 10 years
Low opening PCLP (318.3) driven by low opening shipper nominations
Linepack 18th August 2011
305.0
310.0
315.0
320.0
325.0
330.0
335.0
340.0
345.0
350.0
355.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
Lin
epac
k (m
cm)
-30
-25
-20
-15
-10
-5
0
5
10
15
PC
LP
de
via
tio
n a
nd
No
min
atio
n i
mb
alan
ce
(mc
m)
DFN PCLP Actual National LinepackPCLP deviation from opening Net nomination imbalanceDemand adjusted PCLP deviation from opening
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18th August 2011
Shipper negative nomination imbalances 18th August 2011 (imbalances >1 mcm at 06:00)
-60.0
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce (
mcm
)
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18th August 2011
Shipper positive nomination imbalances 18th August 2011 (imbalances >1 mcm at 06:00)
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00Im
bal
ance
(m
cm)
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19th December 2010Relatively High Actual linepack swing (18.6mcm)
D-1 GBA issued for following day at 18:25
Linepack 19th December 2011
330
335
340
345
350
355
360
365
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
Lin
epac
k (m
cm)
-12
-10
-8
-6
-4
-2
0
2
4
6
8
PC
LP
dev
iati
on
an
d N
om
inat
ion
imb
alan
ce (
mcm
)
DFN PCLP Actual National LinepackPCLP deviation from opening Net nomination imbalanceDemand adjusted PCLP deviation from opening
D-1 GBA issued 18:25
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38
19th December 2010Shipper negative nomination imbalances 19th December 2011 (imbalances >1 mcm at 06:00)
-80.0
-70.0
-60.0
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce (
mcm
)
D-1 GBA issued 18:25
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39
19th December 2010
Shipper positive nomination imbalances 19th December 2010 (imbalances >1 mcm at 06:00)
-10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce (
mcm
)
D-1 GBA issued 18:25
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40
21st December 2010Moderate Actual linepack swing (14mcm)
High opening PCLP (318.5) driven by high opening shipper nominations
Linepack 21st December 2011
340
345
350
355
360
365
370
375
380
385
390
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
05:00
Lin
epac
k (m
cm)
-10
0
10
20
30
40
50
PC
LP
dev
iati
on
an
d N
om
inat
ion
imb
alan
ce (
mcm
)
DFN PCLP Actual National LinepackPCLP deviation from opening Net nomination imbalanceDemand adjusted PCLP deviation from opening
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41
21st December 2010
Shipper negative nomination imbalances 21st December 2011 (imbalances >1 mcm at 06:00)
-120.0
-100.0
-80.0
-60.0
-40.0
-20.0
0.0
20.0
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
00:00
01:00
02:00
03:00
04:00
Imb
alan
ce (
mcm
)
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42
21st December 2010
Shipper positive nomination imbalances 21st December 2010 (imbalances >1 mcm at 06:00)
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
06
:00
07
:00
08
:00
09
:00
10
:00
11
:00
12
:00
13
:00
14
:00
15
:00
16
:00
17
:00
18
:00
19
:00
20
:00
21
:00
22
:00
23
:00
00
:00
01
:00
02
:00
03
:00
04
:00
Imb
ala
nc
e (m
cm
)
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43
Observations
On the 18th large proportion of the nomination imbalance was attributable to two shippers, both of which corrected this before 10:00
On the 19th, on the day we of issued a Day Ahead GBA, there appears to be a move towards balance in shipper nominations coincident with the issue of the GBA, even though the GBA relates to the following gas day.
On the 21st, there is a similar marked change in the balance of nominations, when there was no GBA issued.
On the 21st, a single shipper accounts for a large proportion of both the positive and negative imbalances, under different trading names, leaving a relatively small net imbalance overall.
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GBA Next Steps
Transmission Workgroup 11th October 2011
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45
GBA Next Steps…
Further develop ideas
Present strawman proposal(s) to the industry
Raise Modification Proposal
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Firm Monitor
Transmission Workgroup 11th October 2011
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47
Feedback from industry meetings
Mixed feedback from industry
Not used, so happy with it being removed
Useful indicator of storage ‘requirement’
No suggestions on what information would be useful
Latest update for Firm Monitor space requirement is 94%
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48
Firm Monitor Next Steps…
Further develop ideas
Present strawman proposal(s) to the industry
Raise Modification Proposal
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End
Transmission Workgroup 11th October 2011