1. 1 Interstate Pipeline Gas Quality Primer Business Practices Subcommittee June 15-16, 2004 PIPELINE SEGMENT Wholesale Gas Quadrant North American Energy Standards Board

2. 2 OVERVIEW Basis for Gas Quality Specifications –Development –Criteria –Trade-offs Gas Quality Data –Collection –Availability –Usage Gas Quality Specifications/Applicability –Components –Understanding Conclusions

3. 3 Basis for Gas Quality Specifications Industry Development –First pipelines (1920s – 1930s) were regional Few pipe-to-pipe deliveries –Specific supplies delivered to specific markets –Little concern about variations in supply mix Each system developed criteria for specific safety and market requirements End-use equipment designed and installed based on specific supply availability –Subsequent development of pipeline grid (1970s-1980s) Additional quality criteria applied to specific systems Additional pipe-to-pipe deliveries Minimum coordination of quality specifications at interconnects

4. 4 Gas quality specifications have been developed based on: –Operational Safety –Operational Efficiency Supply availability Market requirements Processing responsibilities –Deliberate trade-offs between economics and requirements of production, transportation and end-use parameters Basis for Gas Quality Specifications

5. 5 Operational Safety –Limitations on harmful components H 2 S – highly poisonous Sulfur – by-products during combustion –Specifications to control damaging properties Water/water vapor content – corrosion Oxygen – corrosion Carbon Dioxide - corrosion Basis for Gas Quality Specifications

6. 6 Operational Efficiency –Btu parameters Throughput capacity –Specific Gravity Gas flow efficiency –Hydrocarbon Liquefiables Capacity restrictions –Inerts Btu impact Emissions concerns Basis for Gas Quality Specifications

7. 7 Gas Quality Trade-offs –After assuring safety, other quality criteria often established to optimize availability of supplies, market requirements and economics Basis for Gas Quality Specifications

8. 8 Gas Quality Data Gas Quality Data Collection – Electronic evaluation (Chromatograph and other instrumentation) Relatively expensive Often telemetered May not be operationally feasible (power/radio) –Sampling – physical evaluation Continuous sample –Gas stream tested for a specified period Spot sample –Gas stream tested at a point in time Other Sample –Random sample/sample period –Equipment in place is pertinent to pipeline and customer requirements –Data requirements may be contract driven

9. 9 Gas Quality Data Data availability –Location Electronic measurement (EMS) vs. charts –Size of meter –Frequency of flow –Support for installation (power, transmission) SCADA –Operational data –Not billing quality information –Timing Measurement parameters –Data availability –Reporting frequency Adjustments –Operational vs. Billing Quality –Not all data is available and/or monitored daily

10. 10 Quality Data Usage –Real Time vs. Periodic Reporting Electronic reporting Sampling frequency –Proprietary Issues Operator-to-operator specific performance issues Within Tariff tolerance is criteria for other performance –Receipt-to-delivery relationships Blending Timing of quality readings (transients) –Delivered quality Specific supply quality may not be an issue Gas Quality Data

11. 11 Gas Quality Specifications/Applicability Typical Pipeline Gas Quality Components –Btu Content (Minimum/Maximum limits) –Hydrogen Sulfide (H 2 S) –Total Sulfur (S) –Nitrogen (N) –Carbon Dioxide (CO 2 ) –Oxygen (O 2 ) –Water and/or Water Vapor –Hydrocarbon Liquefiables –Temperature –Total Inerts –Dust, Gum, Dirt –Other Burnability (HHV, HV, Input Factor, Wobbe) Mercaptans Not all applicable to all pipelines

12. 12 Context of Gas Quality Data –Transient information –Upstream information may not be a predictor of delivery quality Level of data availability/presentation –Pooling/Blending –Reticulated systems (variable direction flows) –Downstream blended data may be more indicative of gas quality performance Gas Quality Specifications/Applicability

13. 13 Conclusions Understanding the context of quality information is critical for its use Not all gas quality information is captured at all points Gas quality at any point is a mix of input qualities/quantities and existing line pack Real-time information is probably not feasible for posting Daily data (if electronic) may be best available information –Blended information (24 hours) –May not be reflective of future flows –May not be available at all locations