Exhibit 23.3 [NETHERLAND, SEWELL & ASSOCIATES, INC. 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, 2002. NETHERLAND, SEWELL & ASSOCIATES, INC. By: /s/ J. Carter Henson, Jr. --------------------------------- J. Carter Henson, Jr. Senior Vice President Houston, Texas March 25, 2003