DN OAD Processes: RG 0316 : Offtake Workstream 8th October 2010

Introduction Overview of DN Flat and Flex capacity requirements Overview of D and D-1 Processes

Overview of DN Flat and Flex capacity requirements

DN Flat and Flex Capacity Requirements Sufficient flat and flex capacity booked to meet 1:20 peak day licence conditions DNs use consistent modelling processes to determine requirements Flat usage generally behaves as modelled Flex usage shows more variation in practice particularly at volumetrically controlled offtakes

Determining LDZ Storage Requirements Empty LDZ storage and possible use of NTS flex Fill LDZ storage and possible use of NTS flex

Factors taken into account to determine requirements Previous demand profiles Latest demand forecasts

Output This is then used to determine flex requirements at individual offtakes

Performance

Key reasons for Flex breaches Demand tracking Reconfiguration of the network Faults Maintenance Flow swaps (Other than in the case of demand tracking, a breach of flex at one offtake is likely to be offset by a reduction in flex usage at another)

Overview of D and D-1 Processes

Definitions: LDZ Demand: LDZ Intake: NTS Intake: Sum of Net Temperature and non-temperature sensitive load including vldmcs etc LDZ Intake: Gas being brought into the LDZ to meet LDZ’s own requirements (demand + stock change), which may be sourced from NTS or NON- NTS offtakes and inter-LDZ transfers (in) NTS Intake: Gas being brought into the LDZ from NTS offtakes only which may be used to satisfy the LDZ’s own requirements and also requirements for other LDZ via inter-LDZ transfers (out)

Information provision at 13:00 D-1 and all other round-up times Forecast LDZ Demand 20 Stock Change 2 LDZ Transfers (in) 0.5 LDZ Transfers (out) 0.1 LDZ Intake 22 NTS Intake* 21.6 Required Flex* 1

Additional information provision at 18:00 D-1 and where changes are required Offtake Profile Nominations 1 value per hour and per offtake

Production of OPNs OPN processes may vary by DN and by LDZ High level process will be similar: Determine NTS Intake Allocate NTS Intake to NTS Offtakes Pressure controlled offtakes are allocated first Volumetrically controlled offtakes are allocated next These slides cover generic core system only

Determine NTS Intake Inputs: NTS Intake* 21.6 Required Flex* 1 Hours when flex is taken, paid back 2 hour / 5% rule (not as defined in OAD)

Allocate NTS Intake to Pressure Controlled Offtakes Inputs: LDZ Demand profile - (total 20) Latest hourly volumes for each pressure controlled offtake Pressure controlled offtakes will be assumed to follow the same profile as LDZ Demand based on the ratios of their most recent actual

Allocate NTS Intake to Volumetrically Controlled Offtakes Inputs: NTS Intake profile - (total 21.6) Sum of Pressure controlled projections (from last slide) Latest hourly volumes for each volumetric offtake

Determine total volumetric intake ie Shortfall (NTS Intake – Pressure controlled projections)