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                                                                    EXHIBIT 5(a)




                                            December 14, 2000





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 $2,000,000,000 of: (i) CMS
Energy Common Stock, $.01 par value ("CMS Energy Common Stock"); (ii) Senior
Debentures of the Company ("Senior Debentures"); (iii) Subordinated Debentures
of the Company ("Subordinated Debentures"); (iv) Trust Preferred Securities of
CMS Energy Trust IV; (v) Trust Preferred Securities of CMS Energy Trust V; (vi)
Guarantee of CMS Energy Corporation with respect to Trust Preferred Securities
of CMS Energy Trust IV and CMS Energy Trust V; (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 Subordinated Debentures are to be issued under an Indenture to be
entered into between the Company and The Bank of New York, as trustee (the
"Subordinated Indenture Trustee"), and one or more supplemental indentures
thereto (collectively, the "Subordinated Indenture"). The Senior Debentures are
to be issued under an Indenture to be entered into between the Company and Bank
One Trust Company, National Association, as trustee (the "Senior Indenture
Trustee"), and one or more supplemental indentures thereto (collectively the
"Senior 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 corporate power and authority: (i) to execute and deliver
          the Senior Indenture and the Subordinated Indenture and the Trust
          Preferred Securities Guarantee, and (ii) to authorize and sell the CMS
          Energy Common Stock, any Stock Purchase Contract or Stock Purchase
          Unit and the Senior Debentures and the Subordinated Debentures
          pursuant to the Senior Indenture and the Subordinated Indenture,
          respectively.

     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 Senior or Subordinated 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) in the case of the Senior Debentures,
          the Senior Indenture shall have been qualified under

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          the Trust Indenture Act and duly executed and delivered by the Company
          and the Senior Indenture Trustee and in the case of the Subordinated
          Debentures, the Subordinated Indenture shall have been qualified under
          the Trust Indenture Act and duly executed by the Company and the
          Subordinated Indenture Trustee; (iii) an appropriate prospectus
          supplement with respect to the particular Senior Debentures or
          Subordinated 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 particular Senior Debentures
          or Subordinated Debentures, as contemplated by the Registration
          Statement and the Senior Indenture or the Subordinated Indenture; (v)
          the supplemental indenture under which the particular Senior
          Debentures or Subordinated Debentures are to be issued shall have been
          duly executed and authenticated as provided in the respective Senior
          Indenture or Subordinated Indenture and such resolutions; and (vi) the
          particular Senior Debentures or Subordinated 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  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 CMS Energy Common Stock, Trust Preferred
          Securities or Subordinated Debentures to be converted into CMS Energy
          Common Stock or Stock Purchase Contracts pursuant to which CMS Energy
          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  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 Subordinated Indenture Trustee under the Subordinated
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 Subordinated Indenture, as to the rights, duties and
obligations of the Subordinated 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