Winter Wednesday - Balancing Withdrawal May Be Unavailable

Monday, January 10, 2005

One very important piece of Pipe Ranger's operations information is Imbalance Gas in Storage, found at the bottom of PG&E Recent Storage Activity.

Imbalance Gas in Storage represents the inventory level of gas available for pipeline balancing services. Many customers know that 50 MMcf/d of injection and 70 MMcf/d of withdrawal are reserved for pipeline balancing. It is also important to remember that 2.2 Bcf of inventory are reserved for pipeline balancing. Addendum: Effective January 1, 2004, firm storage assets dedicated to balancing increased to 75 MMcf/d of injection and withdrawal and 4.04 Bcf of inventory.

Right now, the inventory of Imbalance Gas in Storage is nearing critical levels. If Imbalance Gas in Storage falls to zero, Pacific Gas and Electric Company will suspend pipeline withdrawal for balancing.

Recent and consistent underdeliveries by suppliers have led to frequent withdrawals to balance the system. In turn, Imbalance Gas in Storage has declined rapidly. Aggravating the situation is an Arctic air mass approaching the country. Forecasters predict a severe cold front across much of the United States by next week. Cold weather often exacerbates underdeliveries.

When Imbalance Gas in Storage reaches zero, the entire inventory reserved for pipeline balancing has been withdrawn. Normally, as minimum safe operating limits are approached, balancing gas is withdrawn to maintain pipeline inventory within safe operating limits. However, balancing withdrawals cannot occur without balancing inventory in the ground. Without withdrawals for balancing, the likelihood of low inventory OFOs increases.

If suspended, withdrawal for balancing will not be available until Imbalance Gas in Storage is replenished by positive supplier imbalances (overdeliveries). As soon as the Imbalance Gas in Storage inventory returns to positive levels, withdrawal for balancing will again be available.

What can shippers do to help avoid low inventory OFOs?

  • Balance supply and demand daily
  • Keep an eye on the PG&E Recent Storage Activity

As always, your California Gas Transmission Representative is available to answer any further questions.

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