Winter Update

David Salisbury GCF 25th January 2010

Agenda

Headlines

Background

Process

Types of interruption

Chronology of events

Interruption

How cold was it ?

Implications for the future

Conclusions

Headlines

High levels of demand experienced 4th Jan – 11th Jan

NTS record send out 8th Jan (463 mcm)

4 Gas Balancing Alerts; two potential NGSE

Volume interruption invoked on NGGD networks (EM, NW and EA)

Good response from customers

Continuous review of network operation

All NGGD volume interruption load restored for 9/10; all NSL interruption restored 10/10

Process

Design System

Demand Forecast

Capacity Bookings

Winter Operations Plan

Licence1 in 20 Requirement

Received in May each year

Made through the OCS processProvide signals to NTS wherecapacity required

To flow within design capabilityand booked capacity

Interruption

Types of Interruption

Test – for up to three times a year

Commercial – by shipper

Emergency

Constraint – localised constraint (NSL interruption)

Volume – high level constraint invoked when reach capacity triggers

Chronology (4th – 11th Jan) 4th Jan

very high demand levels forecast for 5th Jan

Forecast to exceed capacity triggers – volume interruption invoked in EM and NW

5th Jan

Continued forecast high demand levels for 6th Jan; exceed capacity triggers – volume interruption in EM, NW

6th Jan

Ditto for 7th Jan but capacity triggers in EA also breached

7th Jan

Modelling data and review of network operation allow increased triggers for 8th Jan

Some volume interruption revoked

8th Jan

Reducing demand allows all volume interruption to be revoked for 9th Jan

9th Jan

Further reducing demand allows all NSL interruption revoked for 10th Jan

Interruption Data

Volume (mcm)

04/10 05/10 06/10 07/10 08/10 09/10 10/10 11/10

EA 0.02 0.04 0.02 0.39 0.02 0.02 0 0

EM 0.07 1.20 2.29 2.57 0.69 0.01 0 0

NW 0.12 1.12 1.12 1.19 0.85 0.08 0 0

No. customers

EA 1 2 1 2 1 1 0 0

EM 1 47 51 52 21 1 0 0

NW 7 45 45 53 38 6 0 0

East Anglia

20.00

22.00

24.00

26.00

28.00

30.00

32.00

Send out

Send out + int

Cap Trig

NSL Trig

East Midlands

East Midlands

30.00

31.00

32.00

33.00

34.00

35.00

36.00

37.00

Send out

Send out + int

Cap Trig

NSL Trig

NorthWest

30.00

32.00

34.00

36.00

38.00

40.00

42.00

44.00

Send out

Send out + int

Cap Trig

NSL Trig

North London

North London

20.00

25.00

30.00

35.00

40.00

45.00

04/01

/201

0

05/01

/201

0

06/01

/201

0

07/01

/201

0

08/01

/201

0

09/01

/201

0

10/01

/201

0

11/01

/201

0

12/01

/201

0

13/01

/201

0

14/01

/201

0

15/01

/201

0

16/01

/201

0

17/01

/201

0

NL

Cap Trig

West Midlands

West Midlands

20.00

22.00

24.00

26.00

28.00

30.00

32.00

34.00

36.00

WM

Cap Trig

How cold was it ?

7 of the 16 coldest days in the last 14 years occurred in w/b 4th JanAverage CWV's

09/0

1/20

10

08/0

1/20

10

07/0

1/20

10

01/0

1/19

97

31/1

2/19

96

06/0

1/20

10

04/0

1/19

97

02/0

1/19

97

07/0

1/19

97

10/0

1/20

10

20/1

2/20

09

04/0

1/20

10

05/0

1/20

10

06/0

1/20

09

03/0

1/19

97

08/0

1/19

97

-2

-1.8

-1.6

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

1

CW

V

Implications for 2011 ?

Much reduced interruptible volume post October 2011 because of DN Interruption Reform

Interruptible load reduces to 0.4 mcm

Network reinforcements on track to be completed ahead of 2011

Anticipated fewer NSLs in winter 2010

Valuable data gathered for:

Future demand forecasts

Network capability

Conclusions

Demand Forecast

Close to peak day ?

Valuable information for future forecasts

Interruption

Good customer response (some potential FTIs)

Network Operation

Networks have stood up well