(a) The amount of power to be extended to an existing customer shall be determined according to this formula:

Customer Contract Rate of Delivery (CROD) today/total project CROD under contract today × project-specific percentage × marketable resource determined to be available at the time future resource extensions begin = CROD extended.

(b) Where contract rates of delivery vary by season, the formula shall be used on a seasonal basis to determine the extended power resource. A similar pro rata approach shall be used for energy extensions.

(c) Determination of the amount of resource available after existing contracts expire, if significantly different from existing resource commitments, shall take place only after an appropriate public process.

(d) The formula set forth in paragraph (a) of this section also should be used to determine the amounts of firm power subject to withdrawal at 5-year intervals after the effective date of the extension to existing customers, except that the percentage used would be up to 1 percent for each of the two withdrawal opportunities, and the formula would use the customer CROD, project CROD and the resource under contract at the time.