Western Gas Interstate Company

Fourth Revised Volume No. 1

Effective Date: 06/01/1997, Docket: RP97-160-001, Status: Effective

First Revised Sheet No. 141 First Revised Sheet No. 141 : Effective

Superseding: ORIGINAL SHEET NO. 141

RATE SCHEDULE RCS

FIRM TRANSPORTATION SERVICE - RELEASED CAPACITY

(continued)

Bidding Shipper(s) submitting the best offer(s)

according to the terms specified by the Releasing

Shipper in its Notice, or, in the absence of such

specified terms, the following:

Net Present Value - the calculation of the net

present value of the reservation charge, as

follows:

NPV = R x C

(1+I)n

where: NPV = Net Present Value

R = Reservation Charge bid

C = Capacity, sated in Dth

I = Commission interest rate

n = exponent signifying term of release,

in months.

If more than one bid has the same value as determined

pursuant to the terms of determining the best offer set

forth herein, then Released Capacity shall be awarded

to Bidding Shipper(s) on the basis of the tie-breaking

method designated by the Releasing Shipper in its

Capacity Release Notice, or in the absence of such

designation, by means of a lottery, until all the

Released Capacity is awarded to Bidding Shippers. A

Bidding Shipper may reject an award of a lesser

quantity of Released Capacity than it bid for. The

Releasing Shipper shall not be entitled to reject any

bid selected as set forth herein.

(d) In no event will an award of Released Capacity be

made for a period exceeding the term of the

Releasing Shipper's Transportation Service

Agreement, or a period of less than one (1) gas

flow Day as defined in the General Terms and

Conditions.