29.2	ISO Tariff Amendments
29.2.1	Amendments to the Body of the ISO Tariff
2.5.27.1	Regulation.
Regulation Up and Regulation Down payments shall be calculated separately.
Quantities.  The following quantity definitions shall be used for each Scheduling Coordinator in
 the settlement process:
AGCUPQDAxt = the Scheduling Coordinator’s total quantity of Regulation Up capacity in Zone X sold through the ISO auction, and scheduled Day-Ahead j for Settlement Period t.
AGCDownQDAxt = the Scheduling Coordinator’s total quantity of Regulation Down capacity in Zone X sold through the ISO auction, and scheduled Day-Ahead j for Settlement Period t.
EnQUnstixt = Uninstructed Imbalance Energy increase or decrease from a Generating Unit i providing Regulation in Zone X in real time Dispatch for Settlement Period t, determined in accordance with the ISO Protocols.
Prices.  The prices in the Settlement process for Regulation Up and Regulation Down shall be those determined in Section 2.5.14.
 Adjustment:  penalty described in Section 2.5.26.
PAGCUpDAxt = the market clearing price, PAGC, in Zone X for Regulation Up capacity in the Day-Ahead market for Settlement Period t.
PAGCDownDAxt = the market clearing price, PAGC, in Zone X for Regulation Down capacity in the Day-Ahead market for Settlement Period t.
Payments.  Scheduling Coordinators for Generating Units providing Regulation Up capacity through the ISO auction shall receive the following payments for Regulation Up:
AGCUpPayxt = AGCUpQDAxt *PAGCUpDAxt -  Adjustment
Scheduling Coordinators for Generating Units providing Regulation Down capacity through the ISO auction shall receive the following payments for Regulation Down:
AGCDownPayxt = AGCDownQDAxt *PAGCDownDAxt – Adjustment
Scheduling Coordinators for Generating Units shall receive the following payment for Energy output from Regulation:

REPAixt	=	the Regulation Energy Payment Adjustment for Generating Unit i in Zone X
		for Settlement Period t calculated as follows:
[(RUPixt * CUP) + (RDNixt * CDN)] * max ($20/MWh, Pxt)
Where
RUPixt	=	the upward range of generating capacity for the provision of Regulation from Generating Unit i in Zone X included in the bid accepted by the ISO for Generating Unit i for Settlement Period t, weighted in proportion to the ISO’s need for upward Regulation  The weighting factors will be specified within a range from 0-100 percent.  The weighting factors will be set at the discretion of the ISO based on system conditions, and will be set at a level that will provide sufficient incentive to the market to supply upward Regulation for the ISO’s purposes of satisfying WSCC criteria and NERC control performance standards.  The ISO shall post the weighting factors consistent with the ISO Weighting Procedure, posted on the ISO website.
RDnixt	=	the downward range of generating capacity for the provision of Regulation for Generating Unit i in Zone X included in the bid accepted by the ISO for Generating Unit i for Settlement Period t, weighted in proportion to the ISO’s need for downward Regulation. The weighting factors will be specified within a range from 0-100 percent.  The weighting factors will be set at the discretion of the ISO based on system conditions, and will be set at a level that will provide sufficient incentive to the market to supply downward Regulation for the ISO’s purposes of satisfying WSCC criteria and NERC control performance standards. The ISO shall post the weighting factors consistent with the ISO Weighting Procedure, posted on the ISO website.
CUP	=	1
CDN	=	1
Pxt	=	the Hourly Ex Post Price for Zone X in Settlement Period t.
The ISO may modify the value of the constants CUP or CDN within a range of 0-1 either generally in regard to all hours or specifically in regard to particular times of the day, after the ISO Governing Board approves such modification, by a notice issued by the Chief Executive Officer of the ISO and posted on the ISO Internet “Home Page,” at http//www.caiso.com, or such other Internet address as the ISO may publish from time to time, specifying the date and time from which the modification shall take effect, which shall be not less than seven (7) days after the Notice is issued.
 
REPA shall not be payable unless the Generating Unit is available and capable of being controlled and monitored by the ISO Energy Management System over the full range of its Scheduled Regulation capacity for the entire Settlement Period at at least the ramp rates (increase and decrease in MW/minute) stated in its bid.  In addition, the total Energy available (RUP plus RDN) may be adjusted to be only RUP or only RDN, a percentage of RUP or RDN, or the sum of RUP and RDN, depending on the needs of the ISO for each direction of Regulation service.