DN Operation Iain Ward DNCC Manager
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)
Daily Operations – Key Stages Forecast Demand Define Diurnal Profile Programme Intakes Manage Demand Changes Respond to NTS Change Requests
Manage LDZ Take, Demand and Stock
Forecast Demand LDZ Level Weather Data (NDM) VLDMC OPNs (DM) Approx 5% Demand Change per 1 deg C
Demands and Temperature Relationship
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
Diurnal Profiles Supply Rate Demand Profile B C AA Storage Requirement A + B - C Empty Holders & Linepack, Fill Holders & Linepack
Manage LDZ Take, Demand and Stock
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
Theddlethorpe Gas ( MJ - m3) Bacton Gas ( MJ/m3) St Fergus / Teesside Gas ( MJ/m3) St Fergus Gas ( MJ/m3) Easington/ Rough Gas ( MJ/m3) St Fergus / Barrow Gas ( MJ/m3) CV Management
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?
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
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.
LDZ 1
LDZ 2