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Assured Offtake Pressures OAD Workgroup 25 th September 2012

Assured Offtake Pressures OAD Workgroup 25 th September 2012. Network Flexibility. Term that National Grid NTS has used in RIIO to identify the additional operational capability required for the NTS to accommodate the changing flow patterns and changing behaviours / requirements of NTS Users

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Assured Offtake Pressures OAD Workgroup 25 th September 2012

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  1. Assured Offtake Pressures OAD Workgroup 25th September 2012

  2. Network Flexibility • Term that National Grid NTS has used in RIIO to identify the additional operational capability required for the NTS to accommodate the changing flow patterns and changing behaviours / requirements of NTS Users • NTS have proposed that this can be achieved through • Rules, Tools or Assets • Optimum solution likely being a combination of all three • Assured Offtake Pressures (AOPs) and associated pressure agreements are some of the existing Rules and Tools that are currently used to manage the NTS/LDZ interface • Optimisation of NTS/DN system investment

  3. Assured Offtake Pressures (AOPs) • AOPs provide DNOs with sufficiently high system input pressures under which to plan, develop and operate their LDZs economically and efficiently • Each Exit Point’s AOPs are applicable for each Day within in a Gas Year and are not linked to demand • The agreed/significant pressures process can be used to agree lower/higher 06:00 operational pressures if required • This process is used on the majority of days

  4. Why Propose Changes to AOPs • NTS investment / capability analysis assumes that AOPs are met at all demand levels • No equivalent of the Agreed Pressures Process for planning purposes • Majority of investment planning analysis for new supplies / storage sites is undertaken at medium to low demand levels

  5. Why do analysis at lower demand levels? • Supply flows, mainly at importation facilities, do not show a correlation with national demand levels Source: National Grid NTS’ RIIO-T1 submission

  6. Entry Capability at lower demand levels • As demand reduces, entry capability of the NTS also reduces as gas needs to be transported further into the system • This results in larger pressure drops making it more difficult to meet AOPs whilst accommodating the level of supply at the terminal. • National Grid NTS may be proposing to invest to meet AOPs that are not required at a particular demand level, leading to potentially inefficient investment

  7. AOPs • It is often difficult for National Grid NTS to agree to DNO requests to increase existing AOPs as they are currently equally applicable to summer and winter demand conditions • If AOPs were linked to demand then • National Grid NTS could be more confident of efficient investment at off-peak demand levels • National Grid NTS and DNOs may be able to agree increases to AOPs at higher demand levels, as these would not apply for the entire gas year • We would not be required to agree appropriate pressures with each DNO, each Day via the Agreed Pressure Process • Would allow GNCC to make more efficient decisions when balancing the network and planning for system access

  8. Understanding AOPs • NTS want to understand each DNOs requirement for high input pressures to their LDZs so that we can consider potential changes to way AOPs are treated. 65% of Peak Source: NTS Demand Side Modelling - Design of Distribution Systems (GL Noble Denton)

  9. Historical (aggregated) LDZ Demand 10% 15% 65% of Peak Forecast 50% of Peak Forecast

  10. Proposal • Proposal to introduce “Bands” of demand • Based on percentage of Peak LDZ demand forecast • For each demand band, DNOs and National Grid NTS would agree: • 06:00 (SOD) Assured Offtake Pressure (by exit point) • 22:00 (EOD) Assured Offtake Pressure (by exit point) • NTS Exit (Flexibility) Capacity (by exit point) given the associated AOPs

  11. Current AOP at a DNO Exit Point Actual DNO Pressure Requirement? Assumed that a minimum level is required below a certain demand threshold Stepped AOPs in line with DNO Requirement Bands of Demand Demand Bands Input Pressure at Exit Point 0% 25% 50% 75% 100% Percentage of Forecast Peak Demand

  12. Next Steps? • National Grid NTS has discussed this potential proposal with some DNOs during its annual network planning meetings • Not all DNOs took up National Grid NTS’ offer of a meeting this year • National Grid NTS is currently investigating the code, systems and process implications • Operational timescales • Agreed 06:00 Pressure process • Low Demand Days • Will provide further updates at future OAD Workgroups • Draft Modification to be available for industry discussion in October / November

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