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Energy Day Timing Issues and Operational Concerns. Pipeline Segment Wholesale Gas Quadrant North American Energy Standards Board Business Practices Subcommittee Energy Day Meetings January 24-25, 2005. WGQ Gas Day Standard. WGQ Gas Day
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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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)
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
Questions? Pipeline Segment Wholesale Gas Quadrant North American Energy Standards Board Business Practice Subcommittee Energy Day Meetings January 24-25, 2005