EXHIBIT 5.1



                                September 7, 2005


Capstone Turbine Corporation
21211 Nordhoff Street
Chatsworth, CA 91311


              Re: Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel to Capstone Turbine Corporation, a Delaware
corporation (the "Company"), in connection with the Registration Statement on
Form S-3 (the "Registration Statement") to be filed by the Company with the
Securities and Exchange Commission relating to the registration of up to
$150,000,000 in aggregate amount of one or more series of (i) debt securities
(the "Debt Securities"), (ii) shares of preferred stock, $0.001 par value (the
"Preferred Shares"), (iii) shares of Common Stock, $0.001 par value, and, if
applicable, certain related rights to purchase Preferred Shares (the "Common
Shares"), or (iv) warrants to purchase Common Shares (the "Common Share
Warrants" and, together with the Debt Securities, the Preferred Shares and the
Common Shares, the "Securities"), all of which Securities may be offered and
sold by the Company from time to time as set forth in the prospectus which forms
a part of the Registration Statement (the "Prospectus"), and as to be set forth
in one or more supplements to the Prospectus (each, a "Prospectus Supplement").

         We have assumed that the issuance, sale, amount and terms of the
Securities to be offered from time to time will be duly authorized and
determined by proper action of the Board of Directors of the Company (each, a
"Board Action") and in accordance with the Company's Second Amended and Restated
Certificate of Incorporation (the "Certificate of Incorporation"), and
applicable Delaware law. We further assume that (i) any senior Debt Securities
will be issued pursuant to an "Indenture" between the Company and a financial
institution identified therein as a trustee (each, a "Trustee"), and (ii) any
Common Share Warrants will be issued under one or more common share warrant
agreements (each, a "Warrant Agreement"), each to be between the Company and a
financial institution identified therein as a warrant agent (each, a "Warrant
Agent").

         In connection with this opinion, we have examined and relied upon such
records, documents and other instruments as in our judgment are necessary or
appropriate in order to express the opinions hereinafter set forth and have
assumed the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, and the conformity to original documents of all
documents submitted to us as certified or photostatic copies.



Capstone Turbine Corporation
September 7, 2005
Page 2


         In rendering the following opinion, we state that we are not admitted
to practice in any state other than the State of Tennessee, and we express no
opinion as to the laws of any jurisdiction other than the State of Tennessee,
the General Corporation Law of the State of Delaware and the federal law of the
United States to the extent specifically referred to herein. All opinions
expressed are as of the date hereof except where expressly stated otherwise.

         Based upon, subject to and limited by the foregoing, we are of the
opinion that, as of the date hereof:

         (1)      When the Registration Statement has become effective under the
                  Securities Act of 1933, as amended (the "Act"), and when a
                  series of the Debt Securities has been (a) duly established by
                  an Indenture or any supplemental indenture thereto, (b) duly
                  authorized and established by applicable Board Action and duly
                  authenticated by the trustee under such Indenture, and (c)
                  duly executed and delivered on behalf of the Company against
                  payment therefor in accordance with the terms of such Board
                  Action, any applicable underwriting agreement, the Indenture
                  and any applicable supplemental indenture thereto, and as
                  contemplated by the Registration Statement and/or the
                  applicable Prospectus Supplement, the Debt Securities will be
                  binding obligations of the Company.

         (2)      When the Registration Statement has become effective under the
                  Act and when a series of the Preferred Shares has been duly
                  authorized and established by applicable Board Action, in
                  accordance with the terms of the Certificate of Incorporation
                  and applicable law, and, upon issuance and delivery of
                  certificates for such series of Preferred Shares against
                  payment therefor in accordance with the terms of such Board
                  Action, any applicable underwriting agreement, and as
                  contemplated by the Registration Statement and/or the
                  applicable Prospectus Supplement, the shares represented by
                  such certificates will be duly authorized and validly issued,
                  fully paid and non-assessable by the Company.

         (3)      When the Registration Statement has become effective under the
                  Act, upon due authorization by Board Action of an issuance of
                  Common Shares, and upon issuance and delivery of certificates
                  for Common Shares against payment therefor in accordance with
                  the terms of such Board Action, any applicable underwriting
                  agreement and as contemplated by the Registration Statement
                  and/or the applicable Prospectus Supplement, the shares
                  represented by such certificates will be duly authorized and
                  validly issued, fully paid and non-assessable by the Company.

         (4)      When the Registration Statement has become effective under the
                  Act and when the Common Share Warrants have been (a) duly
                  established by the related Warrant Agreement, (b) duly
                  authorized and established by applicable Board Action and duly
                  authenticated by the Warrant Agent, and (c) duly



Capstone Turbine Corporation
September 7, 2005
Page 3


                  executed and delivered on behalf of the Company against
                  payment therefor in accordance with the terms of such Board
                  Action, any applicable underwriting agreement, the applicable
                  Warrant Agreement and as contemplated by the Registration
                  Statement and/or the applicable Prospectus Supplement, the
                  Common Share Warrants will be duly authorized and validly
                  issued and fully paid and nonassessable.

         To the extent that the obligations of the Company under an Indenture
may be dependent on such matters, we assume for purposes of this opinion that
the Trustee is duly organized, validly existing and in good standing under the
laws of its jurisdiction of organization; that the Trustee is duly qualified to
engage in activities contemplated by the Indenture; that the Indenture has been
duly authorized, executed and delivered by the Trustee and constitutes the
legally valid and binding obligation of the Trustee enforceable against the
Trustee in accordance with its terms; that the Trustee is in compliance, with
respect to acting as a trustee under the Indenture, with all applicable laws and
regulations; and that the Trustee has the requisite organizational and legal
power and authority to perform its obligations under the Indenture.

         To the extent that the obligations of the Company under any Warrant
Agreement may be dependent on such matters, we assume for purposes of this
opinion that the applicable Warrant Agent is duly organized, validly existing
and in good standing under the laws of its jurisdiction of organization; that
the Warrant Agent is duly qualified to engage in the activities contemplated by
the Warrant Agreement; that the Warrant Agreement has been duly authorized,
executed and delivered by the Warrant Agent and constitutes the legally valid
and binding obligation of the Warrant Agent enforceable against the Warrant
Agent in accordance with its terms; that the Warrant Agent is in compliance,
with respect to acting as a Warrant Agent under the Warrant Agreement, with all
applicable laws and regulations; and that the Warrant Agent has the requisite
organizational and legal power and authority to perform its obligations under
the Warrant Agreement.

         We assume no obligation to advise you of any changes in the foregoing
subsequent to the delivery of this opinion letter. This opinion letter has been
prepared solely for your use in connection with the transmitting for filing of
the Registration Statement on the date of this opinion letter and should not be
quoted in whole or in part or otherwise be referred to, nor filed with or
furnished to any governmental agency or other person or entity, without the
prior written consent of this firm.

         We hereby consent to the filing of this opinion letter as Exhibit 5.1
to the Registration Statement and further consent to the reference to this firm
under the caption "Legal Matters" in the Prospectus constituting a part of the
Registration Statement. In giving this consent, we do not thereby admit that
this firm is an "expert" within the meaning of the Act.



                                      Very truly yours,

                                      /s/ WALLER LANSDEN DORTCH & DAVIS, PLLC