Exhibit 99.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER PURSUANT TO 18 U.S.C. 1350 AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 I, Emily Liggett, certify, pursuant to 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 that the Annual Report of Capstone Turbine Corporation on Form 10-K for the annual period ended December 31, 2002 fully complies with the requirements of Section 13(a) and 15(d) of the Securities Exchange Act of 1934 and that information contained in such Form 10-K fairly presents in all material respects the financial condition and results of operations of Capstone Turbine Corporation. Date: March 31, 2003 By: /s/ EMILY LIGGETT ----------------- Emily Liggett Interim Chief Executive Officer I, Karen Clark, certify, pursuant to 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 that the Annual Report of Capstone Turbine Corporation on Form 10-K for the annual period ended December 31, 2002 fully complies with the requirements of Section 13(a) and 15(d) of the Securities Exchange Act of 1934 and that information contained in such Form 10-K fairly presents in all material respects the financial condition and results of operations of Capstone Turbine Corporation. Date: March 31, 2003 By: /s/ KAREN CLARK --------------- Karen Clark Chief Financial Officer