EXHIBIT 5.1(b)

                 [LETTERHEAD OF SIDLEY AUSTIN BROWN & WOOD LLP]




                                               November 29, 2001
DTE Energy Company
2000 2nd Avenue
Detroit, MI 48226-1279

Ladies and Gentlemen:

         We have acted as special counsel as to the laws of the State of New
York in connection with the registration statement on Form S-3 (the
"Registration Statement") filed by DTE Energy Company, a Michigan corporation
(the "Company"), and DTE Energy Trust I, a Delaware business trust ("DTE Energy
Trust I"), and DTE Energy Trust II, a Delaware business trust ("DTE Energy Trust
II", and together with the DTE Trust I, the "DTE Energy Trusts"), with the
Securities and Exchange Commission for the purpose of registering under the
Securities Act of 1933, as amended (the "Securities Act"), of up to $650,000,000
aggregate initial public offering price of (i)(a) shares of common stock,
without par value (the "Common Stock"), of the Company, (b) debt securities (the
"Debt Securities") of the Company, which may be convertible into shares of
Common Stock or exchangeable into other securities, (c) contracts to purchase
Common Stock (the "Purchase Contracts"), (d) units consisting of Purchase
Contracts and Debt Securities and/or trust preferred securities (the "Preferred
Securities") issued by a DTE Energy Trust, U.S. Treasury securities or other
securities (the "Units"), and (e) Preferred Securities of the DTE Energy Trusts
and (ii) the guarantees (the "Guarantees") of the Company with respect to the
Preferred Securities (the $650,000,000 aggregate initial offering price of
securities being in addition to $350,000,000 aggregate initial offering price of
securities previously registered on registration statement no. 333-58834).


DTE Energy Company
November 29, 2001
Page 2

         The Debt Securities will be issued under an Amended and Restated
Indenture dated as of April 9, 2001, as amended, supplemented or modified from
time to time, between the Company and The Bank of New York, as trustee (the
"Indenture").

         We have examined such documents and records and made such investigation
as we deemed appropriate or necessary, including examining the Registration
Statement and the Indenture.

         Based on the foregoing, subject to the limitations set forth herein and
having regard for such legal considerations we deem relevant, we are of the
opinion that:

         1.  When the Debt Securities have been duly executed and authenticated
             in accordance with the terms of the Indenture and, if applicable, a
             supplemental indenture thereto, and issued and sold as contemplated
             in the Registration Statement, the Debt Securities will constitute
             legal, valid and legally binding obligations of the Company,
             enforceable against the Company in accordance with their terms,
             subject to (i) bankruptcy, insolvency, reorganization, moratorium,
             fraudulent conveyance or similar laws of general application
             relating to or affecting the enforcement of creditors' rights, and
             (ii) the effect of general equitable principles including, without
             limitation, concepts of materiality, reasonableness, good faith and
             fair dealing and the possible unavailability of specific
             performance or injunctive relief, whether considered in a
             proceeding in equity or at law.

         2.  When the Guarantees have been duly executed and delivered by the
             parties thereto, the Guarantees will constitute valid and legally
             binding obligations of the Company, enforceable against the Company
             in accordance with their terms, subject to (i) bankruptcy,
             insolvency, reorganization, moratorium, fraudulent conveyance or
             similar laws of general application relating to or affecting the
             enforcement of creditors' rights, and (ii) the effect of general
             equitable principles including, without limitation, concepts of
             materiality, reasonableness, good faith and fair dealing and the
             possible unavailability of specific performance or injunctive
             relief, whether considered in a proceeding in equity or at law.

         3.  When the Purchase Contracts and Units have been duly executed and
             delivered by the parties thereto, the Purchase Contracts and Units
             will constitute valid and legally binding obligations of the
             Company, enforceable against the Company in accordance with their
             terms, subject to (i) bankruptcy, insolvency, reorganization,
             moratorium, fraudulent conveyance or similar laws of general
             application relating to or affecting the enforcement of creditors'
             rights, and (ii) the effect of general equitable principles
             including, without limitation, concepts of materiality,
             reasonableness, good faith and fair dealing and the possible
             unavailability of specific performance or injunctive relief,
             whether considered in a proceeding in equity or at law.



DTE Energy Company
November 29, 2001
Page 3

         This opinion is confined to and is given on the basis of the laws of
the State of New York as they exist on the date hereof. In giving this opinion,
we have, with your permission, relied as to matters of Michigan law upon the
opinion of Thomas A. Hughes, Associate General Counsel of the Company.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving this consent, we do not admit that we are
within the category of persons whose consent is required under Section 7 of the
Securities Act of 1933, as amended.

                                            Very truly yours,

                                            /s/ Sidley Austin Brown & Wood LLP