DN Operation

1
DN Operation

• Iain Ward
• DNCC Manager

2
Responsibilities

• Licence Holder
• Obligation For 1 In 20 Capacity
• DNCC Operates Networks Under Direction of The DN
• Winter / Summer Operating Strategy
• Booked Capacities
• Short Term Variations
• DN Specific Issues
• DNCC Makes Within-Day Decisions Regarding
• Supply Demand Balancing
• Control of Unbilled Energy
• Plant Outage
• Planned
• Unplanned (faults)

3
Daily Operations Key Stages

• Forecast Demand
• Define Diurnal Profile
• Programme Intakes
• Manage Demand Changes
• Respond to NTS Change Requests

4

• Manage LDZ Take, Demand and Stock

5
Forecast Demand

• LDZ Level
• Weather Data (NDM)
• VLDMC OPNs (DM)
• Approx 5 Demand Change per 1 deg C

6
Demands and Temperature Relationship
7
Define Diurnal Profile

• Diurnal Swing in the Range 12 15
• Significance of Minimum Stock Time
• Storage Deficit in most DNs
• Storage Utilisation in Defined Order
• DN Linepack
• DN LP Storage
• DN Bullets
• NTS Flow Variation

8
Diurnal Profiles
Demand Profile
Empty Holders Linepack,
B
A
A
C
Supply Rate
Storage Requirement A B - C
Fill Holders Linepack
1200
1800
2400
0600
0600
9

• Manage LDZ Take, Demand and Stock

10
Programme Intakes

• Remote Control of Offtake Utilisation
• Notifications to NTS via OPN Process
• Day Ahead and Within Day Considerations
• Meet Sub-LDZ Flow Requirements
• Pressure vs Volumetric Control
• Shrinkage Considerations
• Plant Outage
• Reflective of OCS Where Possible
• Request Additional Flow Flex via OPN Where
  Necessary

11
CV Management
St Fergus / Teesside Gas (39.2 - 41.5 MJ/m3)
St Fergus Gas (40 - 41.5 MJ/m3)
Easington/ Rough Gas (38.1 - 38.7 MJ/m3)
St Fergus / Barrow Gas (38.4 - 41.5 MJ/m3)
Theddlethorpe Gas (38.2 - 38.7 MJ - m3)
Bacton Gas (38.2 - 38.6 MJ/m3)
12
Manage Demand Changes

• Forecast Updated 8 Times Daily (UNC timings) plus
  up to 5 ad-hoc.
• Respond to Revised Weather Data
• Xmas period 2005 5 degree error within day.
• Rebalance DN Supply to Meet Demand Changes
• Revised Offtake Rates
• Impact on storage requirement
• Allocation to Volumetric Offtakes balance effect
  of pressure control?

13
Respond to NTS Change Requests

• NTS To Anticipate Supply Rate Changes,
  Commercially and Physically Driven
• NTS Outages
• Planned e.g. On-Line Inspection
• Un-Planned e.g. Faults
• NTS VLDMC renominations

14
DNCC Offtake Performance

• Booked Flat Capacity Limits Observed at DN Level
• Booked Flow Flex Limits Exceeded at LDZ Level
• Some Offtakes on Some Days
• Pressure Controlled Flows Defined by Consumers
• Within-day demand changes flow through into
  FlowFlex calculation.

15
LDZ 1
16
LDZ 2