Review of System Alerts

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Review of System Alerts

Transmission Workgroup 11th October 2011

2

Agenda

1. Introductions

2. Actions from Last meeting

3. Day ahead

4. Within Day

5. Information

6. GBA Next Steps

7. Firm Monitor


Review of the Gas Balancing Alert arrangements


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.

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)


Day ahead


7

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.

8

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

9

Day Ahead GBA Trigger Level Methodology

What should this include:

NSS calculation

LNG assumption

Beach

Norway

Interconnector

Storage assumption

10

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

11

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?


Within Day GBA


13

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

14

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’

15

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?


Within Day Imbalance


17

Change in Daily Linepack

Pre

ssur

e /

Line

pack

Time

Max Daily Pressure

Min Daily Pressure

06:00 06:00

Change in daily linepack

18

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

19

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

20

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

21

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?


Additional Information


23

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.

24

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?


Nomination imbalance

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.

27

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)

28

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

)

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

30

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

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

)


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


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.

34

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)


35

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

)

36

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)

37

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

)



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

)


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

)


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

)


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

)

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

)

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.


GBA Next Steps


45

GBA Next Steps…

Further develop ideas

Present strawman proposal(s) to the industry

Raise Modification Proposal


Firm Monitor


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%

48

Firm Monitor Next Steps…

Further develop ideas

Present strawman proposal(s) to the industry

Raise Modification Proposal


End


Documents

Review of System Alerts