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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
      –   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

                                                          2
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

                                             3
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
                                                4
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
                                                   5
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


                                                 6
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


                                                       7
Energy Day
Flow Change - Capacity Issue Example


                                Flow
 Receipt Point                                         Delivery Point



 x           Capacity = 240,000 dth/day (10,000 dth/hour)           Y



           X - Receipt Point – Remote set point actuation
           Y - Delivery Point – Manual set point actuation




                                                                        8
Energy Day
Flow 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


                                                           9
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


                                                              10
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




                                                      11
Energy Day
Flow Change – Delivery Assurance Example


                                   Flow
    Receipt Point                                     Delivery Point



X         Capacity = 240,000 dth/day                               Y
              (10,000 dth/hour)



              X - Receipt Point – Manual set point actuation       Z
              Y - Delivery Point – Remote set point actuation
              Z - Delivery Point – Manual set point actuation



                                                                       12
Energy Day
Flow 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



                                                                  13
Energy Day
Flow 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


                                                                    14
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)



                                                         15
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
                                                                  16
                   Questions?
           Pipeline Segment
              Wholesale Gas Quadrant
North American Energy Standards Board

       Business Practice Subcommittee
                 Energy Day Meetings

                    January 24-25, 2005

				
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