Northern Natural Gas Company

Fifth Revised Volume No. 1

Effective Date: 02/25/2006, Docket: RP06-185-000, Status: Effective

Sixth Revised Sheet No. 292 Sixth Revised Sheet No. 292 : Effective

Superseding: Fifth Revised Sheet No. 292

GENERAL TERMS AND CONDITIONS

G. SOL or Critical Day at a Point or Branchline. When an SOL or Critical Day is called at

individual point(s) or on a branchline(s) and the affected Shipper(s) have nominated and

scheduled volumes at a zone level, the DDVC variance will be the difference between the

individual point MDQ as set forth on Appendix B of their Service Agreement and the actual

deliveries for each point in the affected area. Small Customers retain their use of

tolerance and positive DDVC levels as set forth in paragraph B.4 above and SMS when

an SOL has been called to a point or Branchline level and Small Customers are not subject

to the foregoing limitation.

H. System Underrun Limitation (SUL). In the event that the pipeline system operating

integrity is in jeopardy, an SUL may be called. When an SUL is in effect SMS is

available below the throughput scheduled and SMS is available above the scheduled level,

however, no five percent (5%) tolerance will apply below the Shipper's scheduled volume

before the positive DDVC's apply. However, Small Customer's tolerance and Negative DDVC

levels as set forth in paragraph C. above apply at all times, even when an SUL is called.

An SUL may be called for all or part of the system by localizing the smallest affected

area, beginning with individual points, followed by branchline, operational zone,

Market/Field Area, and up to the entire system, in that order. Northern will post the

SUL on the website no later than twenty-seven (27) hours prior to the gas day for which

SUL will be called. Northern will determine the operating status of the pipeline system

using the following criteria: weather forecast; system conditions-line pack, overall

projected pressures at monitored locations and storage conditions; facility status-

horsepower utilization and availability; and overall send-out projections and

availability.

On an SUL day, Northern has the right to require Shippers whose scheduled quantities will

contribute to the SUL situation to source their gas at other receipt points on Northern's

system. A Shipper will not be required to source their gas at other receipt points if

Northern is able to verify and confirm that such Shipper's scheduled quantities are not

contributing to the SUL situation. Northern will require Shippers to move in the

following order:

1. TI Shippers

2. Firm Shippers utilizing Alternate receipt point(s)

3. Firm Shippers with multiple Primary receipt points on their contract

4. Firm Shippers with a single Primary receipt point on their contract.

Shippers must be within their MDQ. Shippers will be required to move on a pro rata basis

within each of the four (4) categories listed above.

Any Shipper required to utilize a different receipt point as stated above, will not be

subject to DDVCs for any day that Shipper is required by Northern to move to a different

receipt point.