The "New Normal" for Maximum Pipeline Capacities, and Firm Capacity Commitments
Tuesday, September 18, 2012
PG&E's California Gas Transmission is implementing a more conservative pressure control strategy across all of its gas systems. CGT has completed the implementation on the backbone system and is currently studying and implementing on the local transmission systems. What are the implications for you, our customers?
With reduced pressure set points, one would expect the maximum capacities on the backbone paths to be reduced. There is a slight decrease to the maximums on the Baja Path, but on average, less than a 2% reduction. The new maximums are now posted on the Pipe Ranger Pipeline Maintenance News page.
For the Redwood Path, sustained high throughput for the past several months has provided us real-time data to help calibrate and fine tune our models. As a result, the recalibration and refinement of our capacity models are actually yielding higher path maximum capacities. Again, the new capacities are now posted on Pipeline Maintenance News.
Implementation is a much greater effort across the local transmission systems, as smaller decreases in pressure have greater implications. CGT is still reviewing and implementing changes across these systems. There is a potential increase in the likelihood of noncore local curtailments during cold weather events this winter. Stay tuned for our annual "Getting Ready for Winter" article, coming in October.
Available Inventory Swing
As reported back in July 2011, pressure reductions due to extensive pipeline inspections and maintenance reduced the amount of available system inventory CGT had to meet hourly and daily fluctuations in demand and supply. The available system inventory dropped from 600 MMcf to 200 MMcf. In December 2011, we were happy to report an increase in available inventory swing, from 200 MMcf to 450 MMcf.
After operating the system at this level over the last ten months, CGT is comfortable that the current level of system inventory swing is now the "new normal." This level of inventory swing will continue to be reflected on the System Inventory Status chart . The inventory bands used to determine if an OFO is necessary will continue to be 3900 MMcf to 4350 MMcf on a day of lower system sendout, and 4000 MMcf to 4450 MMcf on a day of higher system sendout.
Updated Firm Capacity Commitments
As we have done this past year, we are providing updated information in the table below related to committed firm capacities on the Baja and Redwood Paths. In order to get a rough estimate of an individual customer's firm cut level on any day, one can look at the relevant path capacity on the Pipeline Maintenance News page and compare it to the committed firm capacity for that month. For example: if the posted capacity for the Baja Path is 680 MMcf/day and the committed firm capacity for September is 779.7 MDth/day, then a rough expectation for firm volumes to flow would be 87%. Inversely, the rough estimate of levels of firm cuts would be 13%.
|Month||Committed Capacity - Baja Path (MDth/day)||Committed Capacity - Redwood Path (MDth/day)|
Please contact your CGT Representative with any questions.
Copyright © 2009 Pacific Gas and Electric Company.
All rights reserved.