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

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

3. Overview of DN Flat and Flex capacity requirements

4. 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

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

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

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

8. Performance

9. 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)

10. Overview of D and D-1 Processes

11. 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)

12. 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*
Required Flex* 1

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

14. 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

15. 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)

17. 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

19. 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

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