EXHIBIT 23.3 [NSA II LETTERHEAD] CONSENT OF NETHERLAND, SEWELL & ASSOCIATES, INC. We hereby consent to the incorporation by reference on Form 10-K of Calpine Corporation (the "Company") and to the references to this firm for the Company's estimated domestic proved reserves contained on Form 10-K for the year ended December 31, 2003. NETHERLAND, SEWELL & ASSOCIATES, INC. Very truly yours, /s/ J. Carter Henson, Jr. ------------------------- J. Carter Henson, Jr. Senior Vice President Houston, Texas March 11, 2004 Please be advised that the digital document you are viewing is provided by Netherland, Sewell & Associates Inc. (NSAI) as a convenience to our clients. The digital document is intended to be substantively the same as the original signed document maintained by NSAI. The digital document is subject to the parameters, limitations, and conditions stated in the original document. In the event of any differences between the digital document and the original document, the original document shall control and supersede the digital document.