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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
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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
Forecast Demand • LDZ Level • Weather Data (NDM) • VLDMC OPNs (DM) • Approx 5% Demand Change per 1 deg C
20 1ºC = 3% 18 16 14 1ºC = 6% 12 Demands 10 1ºC = 2% 8 6 4 0 5 10 15 20 25 Temperatures Demand 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 Demand Profile Empty Holders & Linepack, B A A C Supply Rate Storage Requirement A + B - C Fill Holders & Linepack 0600 0600 1200 1800 2400
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
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)
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.