September 27, 1999

The Honorable David P. Boergers
Secretary
Federal Energy Regulatory Commission
888 First Street, N.E.
Washington, D.C.  20426

Re:	Docket No. ER99-3289-___

Dear Secretary Boergers:

Enclosed please find an original and fourteen copies of a Notice of Implementation of Payment Calendar Changes (“Notice”) issued on September 24, 1999 by the California Independent System Operator Corporation (“ISO”) pursuant to Amendment No. 17 to the California Independent System Operator Corporation FERC Electric Tariff (“ISO Tariff”).

The ISO filed Amendment No. 17 to the ISO Tariff in the above-captioned docket on June 17, 1999.  Amendment No. 17 consisted of a number of proposed modifications to the ISO Tariff, including Tariff revisions which would revise the ISO's settlement payments calendar.  The changes proposed in Amendment No. 17 would revise the intervals following the Trading Day for meeting certain milestones as reflected in the following chart:

Milestone	Current Calendar	Amendment No. 17 Calendar	
Meter data due to ISO	41 Calendar Days	31 Business Days	
ISO Issues Preliminary Statement	47 Calendar Days	38 Business Days	
Disputes due to ISO	57 Calendar Days	46 Business Days	
ISO Issues Final Statement	61 Calendar Days 	51 Business Days	
Payments due to and from the ISO	65 Calendar Days	56 Business Days	

Because implementation of the revised settlement payments calendar required software modifications, the ISO requested that these Tariff revisions be made effective on the later of September 1, 1999 or at least seven days after the ISO posted notice on the ISO Home Page that the modified software was ready for use.

The Commission accepted the Tariff revisions and proposed effective dates in Amendment No. 17, with certain modifications, by order issued on August 16, 1999.  California Independent System Operator Corporation,  88 FERC ¶ 61,182 (1999).

The enclosed Notice states that the software modifications necessary to implement the approved revisions to the settlement payments calendar are completed except for the modifications to the ISO's Meter Data Acquisition System ("MDAS").  The MDAS modifications are necessary to implement the revisions to Section 10.6.3 of the ISO Tariff which would change the timing for submitting meter data from forty-one (41) Calendar Days to thirty-one (31) Business Days.  This change is reflected on Sheet No. 198 of the ISO Tariff submitted with Amendment No. 17.  Work on the necessary MDAS modifications is proceeding, but due to the ISO's Y2K software deployment freeze, the modifications to the MDAS necessary to implement this component of Amendment No. 17 cannot be put into effect any earlier than February 1, 2000.

The enclosed Notice therefore specifies that all Amendment No. 17 Tariff revisions related to the settlement payments calendar, except for the revisions relating to the submission of meter data, will become effective as of October 1, 1999.  The current provisions of Section 10.6.3, which require the submission of meter data within forty-one (41) Calendar Days of the applicable Trading Day, will remain in effect until the ISO issues a subsequent notice to Market Participants at least seven days before the changes to this provision are to go into effect.  The Market Notice also states that in order to provide Market Participants additional time to submit meter data, the ISO is exercising its authority under Section 13.2(d) of the ISO's Metering Protocol to grant a class exemption.

The ISO states that the enclosed Notice was e-mailed to Market Participants and posted on the ISO Home Page, www.caiso.com, on September 24, 1999, to satisfy the notice requirements of Amendment No. 17.  The ISO further states that it has served the Notice upon each person designated on the official service list for the above-captioned docket, as indicated in the attached certificate of service.

The ISO encloses a notice of filing suitable for publication in the Federal Register and a copy of that notice of filing in WordPerfect format on a diskette. Two extra copies of this filing are also enclosed.  Please stamp these copies with the date and time filed and return it to the messenger.

Respectfully submitted

_____________________________
N. Beth Emery, General Counsel 
and Executive Vice President
Roger E. Smith, 
Senior Regulatory Counsel
The California Independent
   System Operator Corporation
151 Blue Ravine Road
Folsom, CA  95630
(916) 351-2207	_______________________________ 
Kenneth G. Jaffe
David B. Rubin
Sean A. Atkins
Swidler Berlin Shereff Friedman, LLP
3000 K Street, N.W.
Washington, D.C.  20007
(202) 424-7500	

Counsel for the California Independent 
System Operator Corporation

CERTIFICATE OF SERVICE

	I hereby certify that I have this day served the foregoing Notice upon each person designated on the service list compiled by the Secretary in the above-referenced docket.

Dated at Washington, DC, this 27th day of September, 1999.

						_______________________
						Sean A. Atkins
						Counsel for the California Independent
						System Operator Corporation