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

2 WGQ Gas Day Standard WGQ Gas Day – 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 FERC Order No. 587 – July 17, 1996 GISB Standards – Version 1.0 – July 31, 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 ExamplesSafety

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 Receipt Point Delivery Point Capacity = 240,000 dth/day (10,000 dth/hour) X - Receipt Point – Remote set point actuation Y - Delivery Point – Manual set point actuation x Y Flow

9 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

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

13 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

14 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

15 Energy Day Timing Safety Issue Safety is a primary requirement/goal – Physical changes often required to effect flow changes ValvesMeasurementCompression – 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

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