I

Imbalance, Gas
	Synonym:
	Definition:   Producer/Producer - When one or more producers sell or 
                      utilize a volume of natural gas (or energy units) in 
                      excess of their gross working interests.
		      Pipeline/Pipeline - When a pipeline receives a volume of
                      natural gas (or energy units) and redelivers a larger or
                      smaller volume of natural gas under the terms of the 
                      transportation or operating agreement.
		      Producer/Pipeline - When a producer delivers a volume of
                      natural gas (or energy units) that is larger or smaller
                      than the volume of natural gas that the pipeline 
                      redelivers for the producer's account to another party.
		      Pipeline/LDC - When a pipeline receives a volume of 
                      natural gas (or energy units) and redelivers a larger or
                      smaller volume of natural gas to the LDC under the terms
                      of a transportation agreement.
		      LDC/Customer - When an LDC receives a specific volume of
                      natural gas (or energy units) designated for delivery to
                      an individual customer, and redelivers a larger or 
                      smaller volume of natural gas (or energy units) to that
                      customer under terms of a transportation/distribution 
                      agreement or tariff.
Incremental Cost
	Synonym:
	Definition:   Costs incurred when output is increased, usually 
                      calculated as the added cost divided by the added 
                      volume; or costs incurred in excess of a standard or 
                      agreed upon amount to obtain additional or alternative 
                      fuel supplies due to the failure of dedicated reserves.

Indefinite Price Escalator Clauses
	See Area Rate Clause

Independent Marketer
	Synonym:
	Definition:   A company that buys and resells gas for fee and that is
                      not affiliated with any interstate pipeline or 
                      corporation that has an interstate pipeline subsidiary.
Independent Producer
	Synonym:
	Definition:   Usually a company that produces natural gas and is not 
                      involved in transportation, marketing or other gas 
                      operations.
Index Price
	Synonym:
	Definition:   A pricing arrangement which ties the sales price to a 
                      publicly available price, such as a pipeline or LDC 
                      tariff.  Indices are also posted regularly in numerous 
                      trade publications, representing the best judgment of 
                      their publishers.
Infill Drilling
	Synonym:
	Definition:   The process of drilling additional wells within the 
                      defined pool outline of a natural gas pool for the 
                      purpose of increasing reserves and/or productive 
                      capacity.
Inflation Adjustment Factor
	Synonym:
	Definition:   A monthly factor based on the annual rate of inflation 
                      used to calculate the Natural Gas Policy Act maximum 
                      lawful ceiling prices.
Initial Delivery
	Synonym:
	Definition:   The first gas volume to flow under an agreement at a new
                      facility or for a new contract.
Initial Established Reserves
	Synonym:
	Definition:   Established reserves prior to the deduction of any 
                      production.
Interconnections
	Synonym:      Interconnect, Interchange
	Definition:   A facility at which two companies physically connect 
                      for the purpose of transferring gas.
Interruptible Service
	Synonym:      Nonfirm, Noncore, Best Efforts
	Definition:   Transportation or sales service which is subject to 
                      interruption at the option of any of the involved 
                      parties (seller, pipeline, LDC, buyer) because of energy
                      shortages, capacity constraints or economic 
                      considerations.
Interstate
	Synonym:      Across State
	Definition:   (1) Natural gas that is produced in one state and 
                      transported by an interstate pipeline to be sold and 
                      consumed in another.  (2) A pipeline whose facilities 
                      cross state lines.
Interstate Natural Gas Association of America
	Synonym:      INGAA
	Definition:   Association of interstate pipelines.

Intrastate
	Synonym:      Within State
	Definition:   (1) Natural gas that is sold and consumed in the state
                      where it was produced and is not commingled with gas in
                      interstate commerce.  (2) An intrastate pipeline 
                      maintains facilities that do not cross state lines.