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                                                                    EXHIBIT 5(a)




                                            December 14, 1998





CMS Energy Corporation
Fairlane Plaza South
330 Town Center Drive
Suite 1100
Dearborn, MI  48126

Ladies and Gentlemen:

     I am the Assistant General Counsel of CMS Energy Corporation, a Michigan
corporation ("CMS Energy" or the "Company"), and have acted as such in
connection with the Registration Statement on Form S-3 (the "Registration
Statement") being filed by the Company with the Securities and Exchange
Commission (the "Commission") under the Securities Act of 1933, as amended (the
"Securities Act"), relating to the registration of $1,500,000,000 of: (i) CMS
Energy Common Stock, $.01 par value ("CMS Energy Common Stock"); (ii) CMS Energy
Class G Common Stock, no par value ("Class G Common Stock"); (iii) Subordinated
Debentures of the Company ("Debentures"); (iv) Trust Preferred Securities of CMS
Energy Trust II; (v) Trust Preferred Securities of CMS Energy Trust III; (vi)
the guarantee of the Trust Preferred Securities by the Company ("Trust Preferred
Securities Guarantee"); (vii) Stock Purchase Contracts of the Company; and
(viii) Stock Purchase Units of the Company. (The offered securities,
collectively, the "Securities".) The Trust Preferred Securities Guarantee is to
be issued pursuant to a Trust Preferred Securities Guarantee Agreement (the
"Trust Preferred Securities Guarantee Agreement") to be entered into between the
Company and The Bank of New York, as trustee (the "Guarantee Trustee"). The
Debentures are to be issued under an Indenture to be entered into between the
Company and The Bank of New York, as trustee (the "Indenture Trustee"), and one
or more supplemental indentures thereto (collectively, the "Indenture").
Capitalized terms not otherwise defined herein have the respective meanings
specified in the Registration Statement.

     In rendering this opinion, I have examined and relied upon a copy of the
Registration Statement. I have also examined, or have arranged for the
examination by an attorney or attorneys under my general supervision, originals,
or copies of originals certified to my satisfaction, of such agreements,
documents, certificates and other statements of governmental officials and other
instruments, and have examined such questions of law and have satisfied myself
as to such matters 


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of fact, as I have considered relevant and necessary as a basis for this
opinion. I have assumed the authenticity of all documents submitted to me as
originals, the genuineness of all signatures, the legal capacity of all natural
persons and the conformity with the original documents of any copies thereof
submitted to me for examination.

     I note that the issuance of the Trust Preferred Securities is governed by
the laws of the State of Delaware. Any matters relating to Delaware law will be
opined upon by Skadden, Arps, Slate, Meagher & Flom LLP.

     Based on the foregoing, it is my opinion that:

     1.   The Company is duly incorporated and validly existing under the laws
          of the State of Michigan.

     2.   The Company has the corporate power and authority: (i) to execute and
          deliver the Indenture, the Trust Preferred Securities Guarantee, and
          any Stock Purchase Contract or Stock Purchase Unit; and (ii) to
          authorize and sell the Debentures pursuant to the Indenture, the CMS
          Energy Common Stock and the Class G Common Stock.

     3.   The Trust Preferred Securities Guarantee will be a legally issued and
          binding obligation of the Company (except to the extent enforceability
          may be limited by applicable bankruptcy, insolvency, reorganization,
          moratorium, fraudulent transfer or other similar laws affecting the
          enforcement of creditors' rights generally and by the effect of
          general principles of equity, regardless of whether enforceability is
          considered in a proceeding in equity or at law) when: (i) the
          Registration Statement, as finally amended (including any necessary
          post-effective amendments), shall have become effective under the
          Securities Act; (ii) the Trust Preferred Securities Guarantee shall
          have been qualified under the Trust Indenture Act of 1939, as amended
          (the "Trust Indenture Act"), and duly executed and delivered by the
          Company and the Guarantee Trustee; (iii) the Trust Preferred
          Securities shall have been legally issued; and (iv) the Trust
          Preferred Securities Guarantee shall have been duly executed and
          delivered as provided in the Trust Preferred Securities Guarantee
          Agreement.

     4.   The Debentures will be legally issued and binding obligations of the
          Company (except to the extent enforceability may be limited by
          applicable bankruptcy, insolvency, reorganization, moratorium,
          fraudulent transfer or other similar laws affecting the enforcement of
          creditors' rights generally and by the effect of general principles of
          equity, regardless of whether enforceability is considered in a
          proceeding in equity or at law) when: (i) the Registration Statement,
          as finally amended (including any necessary post-effective
          amendments), shall have become effective under the Securities Act;
          (ii) the Indenture shall have been qualified under

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          the Trust Indenture Act and duly executed and delivered by the Company
          and the Indenture Trustee; (iii) an appropriate prospectus supplement
          with respect to the particular Debentures then being sold by the
          Company shall have been filed with the Commission pursuant to Rule 424
          under the Securities Act; (iv) the Company's Board of Directors or
          duly authorized committee thereof shall have duly adopted final
          resolutions authorizing the issuance and sale of the Debentures, as
          contemplated by the Registration Statement and Indenture; (v) the
          supplemental indenture under which the particular Debentures are to be
          issued shall have been duly executed and authenticated as provided in
          the Indenture and such resolutions; and (vi) the Debentures shall have
          been duly delivered to the purchasers thereof against payment of the
          agreed consideration therefor.

     5.   The Stock Purchase Contracts and the Stock Purchase Units, when
          issued and sold, will be legally issued and binding obligations of the
          Company (except to the extent enforceability may be limited by
          applicable bankruptcy, insolvency, reorganization, moratorium,
          fraudulent transfer or other similar laws affecting the enforcement of
          creditors' rights generally and by the effect of general principles of
          equity, regardless of whether enforceability is considered in a
          proceeding in equity or at law) when: (i) the Registration Statement,
          as finally amended (including any necessary post-effective
          amendments), shall have become effective under the Securities Act;
          (ii) an appropriate prospectus supplement with respect to the
          particular Stock Purchase Contracts and the particular Stock Purchase
          Units then being sold by the Company shall have been filed with the
          Commission pursuant to Rule 424 under the Securities Act; and (iii)
          the Stock Purchase Contracts under which the CMS Energy Common Stock
          are to be purchased shall have been duly executed and delivered as
          provided in the Stock Purchase Contracts.

     6.   The CMS Energy Common Stock and the Class G Common Stock will be
          legally issued, fully paid and non-assessable when: (i) the
          Registration Statement, as finally amended, shall have become
          effective under the Securities Act; (ii) the Company's Board of
          Directors or a duly authorized committee thereof shall have duly
          adopted final resolutions authorizing the issuance and sale of the
          Class G Common Stock, the CMS Energy Common Stock, Trust Preferred
          Securities or Debentures to be converted into CMS Energy Common Stock
          or Stock Purchase Contracts pursuant to which CMS Energy Common Stock
          or Class G Common Stock may be purchased, as contemplated by the
          Registration Statement and prospectus supplement relating thereto; and
          (iii) upon delivery, purchase or conversion, as the case may be,
          certificates representing the CMS Energy Common Stock or Class G
          Common Stock shall have been duly executed, countersigned and
          registered and duly delivered to the purchasers thereof against
          payment of the agreed consideration therefor.


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     For purposes of this opinion, I have assumed that there will be no changes
in the laws currently applicable to the Company and that such laws will be the
only laws applicable to the Company.

     I do not find it necessary for the purposes of this opinion to cover, and
accordingly I express no opinion as to, the application of the securities or
blue sky laws of the various states to the execution and delivery of the Trust
Preferred Securities Guarantee or the sale of the Securities.

     I am a member of the bar of the State of Michigan and I express no opinion
as to the laws of any jurisdiction other than the State of Michigan and the
federal law of the United States of America. I note that the rights, duties and
obligations of the Indenture Trustee under the Indenture are stated to be
governed and construed in accordance with the laws of the State of New York.
However, for purposes of paragraph 4 above, I have assumed that the Indenture,
as to the rights, duties and obligations of the Indenture Trustee, is stated to
be governed by the laws of the State of Michigan.

     I hereby consent to the filing of this opinion as an exhibit to the
Company's Registration Statement on Form S-3 relating to the Securities and to
all references to me included in or made a part of the Registration Statement.

                                         Very truly yours,



                                         /s/ Michael D. Van Hemert
                                         -------------------------
                                         Michael D. Van Hemert