Energy Day Timing Issues and Operational Concerns

1. Energy Day Timing Issues andOperational Concerns Pipeline Segment Wholesale Gas Quadrant North American Energy Standards Board Business Practices Subcommittee Energy Day Meetings January 24-25, 2005

2. WGQ Gas Day Standard • WGQ Gas Day • 1.3.1 Standard Time for the gas day should be 9:00 a.m. to 9:00 a.m. (Central Clock Time) * • Significant requirement – flow change times should have a high degree of operational reliability • Capacity optimization • Delivery assurance • Safety (MAOP) • Time required to provide reliability * Adopted March 7, 1996 – Executive Committee – GISB FERC Order No. 587 – July 17, 1996 GISB Standards – Version 1.0 – July 31, 1996

3. Energy Day Flow Change Time Requirement – Overview • Flow planning • Operational flexibility • Issues related to non-coincident nomination and flow changes • Operational flexibility requirements • Flow rate characteristics • Examples • Safety

4. Energy Day Flow Change Time Requirement • Flow planning • Confirmation of supplies and markets • Coordination of resources and requirements • Operational changes necessary after scheduling • Flow rates changes resulting from scheduling can be anticipated (or planned for) • Flows can be optimized to meet daily quantity

5. Energy Day Flow Change Time Requirement • Operational flexibility requirements • Time to pre-position gas • Optimize use of compression • Optimize pipeline pressures • Flow changes coordinated between receipt and delivery • Minimizes unnecessary line pack changes • Minimizes operational imbalances • Optimizes capacity availability

6. Energy Day Flow Change Time Requirement • Flow rate characteristics • 25 to 30 mph • Rate changes are not instantaneous • Affected by line pack and pressures • Pre-positioning for anticipated loads • Compression set up • Adjustability of intra-day flow rates to meet end-of-day scheduled quantities

7. Energy Day Flow Change Time Requirement • Pipeline capacity is impacted by • Daily flow rates • Daily scheduled quantities • Scheduled flow changes not made on time • Capacity Example • Scheduled flow change from Day 1 to Day 2 • Flow change does not occur until several hours after scheduled time

8. Energy Day Flow Change - Capacity Issue Example Flow Receipt Point Delivery Point x Y Capacity = 240,000 dth/day (10,000 dth/hour) X - Receipt Point – Remote set point actuation Y - Delivery Point – Manual set point actuation

9. Energy DayFlow Change - Capacity Issue Example • Nominations • Day 1: Nomination and flow 120,000 dth (5,000 dth/hour) • Day 2: Nomination 240,000 dth (10,000 dth/hour) • Operational changes • X - Receipt Point – Change at start of Gas Day • Y - Delivery Point – Change 6 hours after start of Gas Day

10. Energy Day Flow Change - Capacity Issue Example • Daily flow at receipt point • 10,000 dth/hour X 24 hours = 240,000 dth • Daily flow at delivery point • 5,000 dth/hour X 6 hours = 30,000 dth • 10,000 dth/hour X 18 hours = 180,000 dth • Delivery total = 210,000 dth • Consequences • 30,000 dth shortfall at delivery point • 30,000 dth increase in line pack • 30,000 dth imbalance on pipeline

11. Energy Day Flow Change Time Requirement • Pipeline delivery reliability is impacted by • Pressure at delivery point • Line pack in place • Daily scheduled quantities • Delivery reliability example • Scheduled flow change from Day 1 to Day 2 • Line pack/supplies not in place until several hours after scheduled time

12. Energy DayFlow Change – Delivery Assurance Example Flow Receipt Point Delivery Point Y X Capacity = 240,000 dth/day (10,000 dth/hour) Z X - Receipt Point – Manual set point actuation Y - Delivery Point – Remote set point actuation Z - Delivery Point – Manual set point actuation

13. Energy DayFlow Change – Delivery Assurance Example • Nominations • Day 1: Nomination and flow – 120,000 dth (5,000dth/hour) • X to Y = 60,000 dth (2,500 dth/hour) • X to Z = 60,000 dth (2,500 dth/hour) • Day 2: Nomination – 180,000 dth (7,500 dth/hour) • X to Y = 120,000 dth (5,000 dth/hour) • X to Z = 60,000 dth (2,500 dth/hour) • Operational changes • X - Receipt Point – Change 6 hours after start of Gas Day • Y - Delivery Point – Change set point at start of Gas Day • Z - Delivery Point – No set point change required

14. Energy DayFlow Change – Delivery Assurance Example • Day 2 daily flow at receipt point X • 5,000 dth/hour X 6 hours = 30,000 dth • 7,500 dth /hour X 18 hours = 135,000 dth • Receipt total = 165,000 dth • Scheduled flow = 180,000 dth • Day 2 daily flow at delivery point Y • 5,000 dth /hour X 24 hours = 120,000 dth • Scheduled flow = 120,000 dth • Day 2 daily flow at delivery point Z • 0 dth/hour X 6 hours = 0 dth • 2,500 dth/hour X 18 hours = 45,000 dth • Delivery total = 45,000 dth • Scheduled flow = 60,000 dth • Consequences • 15,000 dth shortfall at receipt point X • 15,000 dth shortfall at delivery point Z • No change in line pack

15. Energy Day Timing Safety Issue • Safety is a primary requirement/goal • Physical changes often required to effect flow changes • Valves • Measurement • Compression • Night operations are not desirable • Visibility • Travel conditions • Availability of other services (assistance, communications, EMT, etc)

16. Energy Day Flow Change Time Requirement Summary • Flow planning • Confirmations/coordination • Gas pre-positioning • Operational flexibility • Gas pre-positioning • Compression and measurement set-up • Set point / flow control • Manage physical flow rates • Achieve daily quantities • Issues related to non-coincident nomination and flow changes • Physical over / under deliveries • Limited by pipeline ability to absorb swings • May include the availability of system storage • Increased imbalances • Loss of useful capacity • Operational shortfalls / failures • Safety

17. Questions? Pipeline Segment Wholesale Gas Quadrant North American Energy Standards Board Business Practice Subcommittee Energy Day Meetings January 24-25, 2005