This excerpt taken from the XEL 8-K filed Jan 16, 2008.
Section 15.3 Notices.
(a) Any notice or demand which by any provision of this Indenture is required or permitted to be given or served by the Trustee or by the Securityholders on the Company may be given or served by being deposited
postage prepaid in a post office letter box addressed (until another address is filed by the Company with the Trustee) at the principal executive offices of the Company, to the attention of the Secretary. Any notice, direction, request or demand by any Securityholder or the Company to or upon the Trustee shall be deemed to have been sufficiently given or made, for all purposes, if given or made in writing at the corporate trust office of the Trustee, Attention: Xcel Energy Administrator, Corporate Trust Department.
(b) The Company shall provide any notices required under this Indenture by publication, but only to the extent that such publication is required by the TIA, the rules and regulations of the Commission or any securities exchange upon which any series of Securities is listed.