Unlike interruptible pools, which cash out each month, firm pools will carry an over/under balance forward and a supplier will repay in gas, for any PGW stored gas used by his customers over the winter months (November – March). Assuming that a pool does use some of PGW’s stored gas over the winter, repayment of that gas, or under-shipping if the pool used less gas than was delivered, will take place over the shoulder and summer months as scheduled by PGW.

A pool’s usage will be estimated by the system at the end of each calendar month, then finally reconciled 45-60 days later, after usage records for pool customers have been collected from all 22 billing cycles, any missing or estimated meter reads have been rectified, etc.

The meter-reading and billing cycles for most monthly-metered customers will cross over calendar months, beginning in one month and ending in the next. Based on actual weather, the system will assign how much of the consumption was used in the calendar month to be reconciled, and how much will be carried forward to the next calendar period, and aggregate this information at the pool level.

Gas payback quantities will be determined based on any difference between quantity delivered and quantity calculated to be used by the pool. Then, the payback quantity will be spread evenly over the April – October repayment period and added to both capacity and DDQ. This figure will be recalculated and adjusted every month based on new data on deliveries vs. usage.

Although the method of calculating capacity release provides a generous margin, and will certainly allow a supplier to bring in all the gas his customers use over the course of a year, it is likely that a pool composed largely of heating customers will used some quantity of gas from PGW’s storage and LNG production during a cold winter. On a Design Day (zero degrees Fahrenheit), PGW brings in only 40% of the necessary gas supply via Firm Transportation capacity on the pipelines, and provides 60% of the supply from storage and LNG.