The glossary of terms is arranged alphabetically. Click on the
letters below to find terms beginning with that letter.
Imbalance: Discrepancy between the amount a
shipper contracted to use or transport and actual volumes used
or transported. Shippers may be forced to pay an imbalance
penalty for variances greater than a certain percentage.
Marketers sometimes take responsibly to balance loads so their
customers can avoid penalties.
Incremental Rates: The allocation of cost for
an additional service or construction project directly to those
who benefit from the service instead of rolling it into overall
rates. To determine the incremental unit cost, the added cost is
divided by the added capacity or output.
Indexing: Tying the commodity price in a
contract to other published prices, such as NYMEX prices, spot
prices for gas or alternate fuels, or general indexes like the
Government Consumer Price Index or Producer Price Index.
Interruptible Service: Gas service subject to
interruption at the option of the pipeline. Also referred to as
"best efforts." Tariffs for interruptible service are cheaper
than firm service. Interstate Gas: Gas transported through
interstate pipelines to be sold and consumed in states other
than the one in which it was produced. Also refers to gas
produced in the federal domain of the Outer Continental Shelf.
Intrastate Gas: Gas sold and consumed in the
state in which it was produced and not transported in interstate
IT: Interruptible transportation.