ATTACHMENT B

AMENDMENT NO. 21 TARIFF REVISIONS

28.  TEMPORARY RULE DISQUALIFYING CERTAIN ENERGY AND ANCILLARY SERVICE BIDS

28.1 	Application and Termination

The temporary change disqualifying certain Energy and Ancillary Service bids set out in Section 28.2 shall continue in effect until November 15, 2000, unless its effectiveness is extended by order of the FERC.

28.2	Disqualification of Certain Energy and Ancillary Service Bids

The ISO may establish price levels for the Imbalance Energy market and/or for any Ancillary Service market above which any bid for a Settlement Period to which the price level applies will be rejected.  The ISO shall establish such price levels in accordance with criteria adopted by the ISO Governing Board from time to time and shall publish such price levels on WEnet or the ISO Home Page in advance of the first Settlement Period for which the ceiling price levels apply.  

SBP 4.6	[NOT USED]