<PAGE>

           As Filed with the Securities and Exchange Commission on June 28, 2002
                                                         Registration No. 333 --

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933

                           --------------------------


                               SEMCO ENERGY, INC.

               (Exact name of issuer as specified in its charter)


               Michigan                                  38-2144267
     (State or other jurisdiction           (I.R.S. Employer Identification No.)
  of incorporation or organization)


         28470 13 Mile Road, Suite 300, Farmington Hills, Michigan 48334
               (Address of Principal Executive Offices) (Zip Code)


                         SEMCO Energy, Inc. 401(k) Plan
                            (Full title of the plan)


                                Arnold R. Madigan
                       Vice President and General Counsel
                               SEMCO Energy, Inc.
                          28470 13 Mile Road, Suite 300
                        Farmington Hills, Michigan 48334
                     (Name and Address of agent for service)
           Telephone number, including area code, of agent of service:
                                  248-702-6208

                          Copies of Communications to:
                               Verne C. Hampton II
                              Dickinson Wright PLLC
                         500 Woodward Avenue, Suite 4000
                             Detroit, Michigan 48226

                  Approximate date of proposed public offering:
 As soon as practicable after the effective date of this Registration Statement

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>

                                                  Proposed Maximum                 Proposed
 Title of Securities        Amount to be         Offering Price Per           Maximum Aggregate            Amount of
   to be Registered          Registered                 Share                   Offering Price          Registration Fee
<S>                        <C>                   <C>                         <C>                       <C>

Common Stock ($1 par        400,000 shs.                $7.80                     $3,120,000                $287.04
value)

</TABLE>


*Based upon the market price on June 21, 2002


<PAGE>





                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


ITEM 3.        INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

SEMCO Energy, Inc. (the "Company") hereby incorporates by reference in this
Registration Statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission") under the Securities
Exchange Act of 1934, as amended (the "Exchange Act"):

                  1.       The Company's Annual Report on Form 10-K for the year
ended December 31, 2001.

                  2.       The Company's Quarterly Report on Form 10-Q for the
quarter ended March 31, 2002.

                  3.       The description of the Common Stock, $1.00 par value,
of the Company set forth in the Prospectus of the Company dated July 24, 1998
which was part of Amendment No. 1 to Registration Statement No. 333-58715.

All documents subsequently filed with the Commission by the Company pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold shall be
deemed to be incorporated herein by reference and to be a part hereof from the
dates of filing of such documents.

ITEM 4.        DESCRIPTION OF SECURITIES

Not Applicable.

ITEM 5.        INTEREST OF NAMED EXPERTS AND COUNSEL

Not Applicable.

ITEM 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS

The Company's Bylaws and the Michigan Business Corporation Act permit the
Company's officers and directors to be indemnified under certain circumstances
for expenses and in some instances, for judgments, fines or amounts paid in
settlement of civil, criminal, administrative and investigative suits or
proceedings, including those involving alleged violations of the Securities Act
of 1933, as amended (the "Act"). In addition, the Company maintains directors'
and officers' liability insurance which, under certain circumstances, would
cover alleged violation of the Act. Insofar as indemnification for liabilities
arising under the Act may be permitted to officers and directors pursuant to the
foregoing provisions, the Company has been informed that, in the opinion of the
Securities and Exchange Commission, such indemnification is against public
policy as expressed in the Act and is, therefore, unenforceable. Therefore in
the event that a claim for such indemnification is asserted by any officer or
director, the Company (except insofar as such claim seeks reimbursement by the
Company of the expenses paid or incurred by an officer or director in the
successful defense of any action, suit or proceeding) will, unless the matter
has heretofore been adjudicated by precedent deemed by the Company to be
controlling, submit to a court of appropriate jurisdiction the question of
whether or not the indemnification by it is against public policy as expressed
in the Act and will be governed by the final adjudication of such issue.

ITEM 7.        EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable.


                                      -1-

<PAGE>




ITEM 8.        EXHIBITS

The following exhibit is filed herewith:

         Exhibit
         Number            Exhibit

           5               Opinion and consent of Dickinson Wright PLLC

The undersigned Company will submit the amended SEMCO Energy, Inc. 401(k) Plan
to the Internal Revenue Service ("IRS") in a timely manner to assure compliance
with the requirements of ERISA and will make all changes required by the IRS in
order to qualify the Plan.


ITEM 9.        UNDERTAKINGS

The undersigned Company hereby undertakes: 1. To file, during any period in
which offers or sales are being made, a post-effective amendment to this
Registration Statement: (i) to include any Prospectus required by Section 10(a)
(3) of the Securities Act of 1933; (ii) to reflect in the Prospectus any facts
or events arising after the effective date of the Registration Statement (or the
most recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the
Registration Statement; (iii) to include any material information with respect
to the plan of distribution not previously disclosed in the Registration
Statement or any material change to such information in the Registration
Statement; provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
apply if the information required to be included in a post-effective amendment
by those paragraphs is contained in periodic reports filed by the Company
pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934
that are incorporated by reference in the Registration Statement. (2) That, for
purposes of determining any liability under the Securities Act of 1933, each
such post-effective amendment shall be deemed to be a new Registration Statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof. (3)
To remove from registration by means of a post-effective amendment any of the
securities being registered which remain unsold at the termination of the
offering.

The undersigned Company hereby undertakes that, for purposes of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act
of 1934 that is incorporated by reference in the Registration Statement shall be
deemed to be a new Registration Statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act of
1933 may be permitted to directors, officers and controlling persons of the
Company pursuant to the foregoing provisions, or otherwise, the Company has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Company of expenses incurred or
paid by a director, officer or controlling person of the Company, in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question of whether or not such indemnification by it is
against public policy as expressed in the Act and will be governed by the final
adjudication of such issue.



                                      -2-

<PAGE>




                                   SIGNATURES


               Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement or amendment thereto to be signed on its behalf by the undersigned,
thereunto duly authorized, in the City of Farmington Hills and State of Michigan
on June 20, 2002.


                                SEMCO ENERGY, INC.

                                      By    /s/ Marcus Jackson
                                        ----------------------------------------
                                            (Marcus Jackson)
                                            Chairman of the Board, President and
                                            Chief Executive Officer



               Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement or amendment thereto has been signed below by the
following persons in the capacities indicated on June 20, 2002.

<TABLE>
<CAPTION>

SIGNATURE                                              TITLE                             SIGNATURE                      TITLE
<S>                                       <C>                                        <C>                              <C>

         /s/ Marcus Jackson               Chairman of the Board,                     /s/ John R. Hinton                Director
         ------------------               President and Chief Executive              -------------------
         (Marcus Jackson)                 Officer (Principal Executive               (John R. Hinton)
                                          Officer) and Director


         /s/ John E. Schneider            Senior Vice President,                     /s/ Harvey I. Klein               Director
         ---------------------            Treasurer and Chief Financial              ------------------
         (John E. Schneider)              Officer (Principal Financial               (Harvey I. Klein)
                                          Officer)


         /s/ John M. Albertine            Director                                   /s/ Frederick S. Moore            Director
         ---------------------                                                       ----------------------
         (John M. Albertine)                                                         (Frederick S. Moore)


         /s/ Edward J. Curtis             Director                                   /s/ Thomas W. Sherman             Director
         --------------------                                                        ---------------------
         (Edward J. Curtis)                                                          (Thomas W. Sherman)


         /s/ John T. Ferris               Director                                   /s/ Edith A. Stotler              Director
         ------------------                                                          --------------------
         (John T. Ferris)                                                            (Edith A. Stotler)


         /s/ Michael O. Frazer            Director                                   /s/ Donald W. Thomason            Director
         ---------------------                                                       ----------------------
         (Michael O. Frazer)                                                         (Donald W. Thomason)

</TABLE>




                                      -3-



<PAGE>








                                  Exhibit Index



Exhibit
Number                                Exhibit
-------                               -------


    5                           Opinion and consent of Dickinson Wright PLLC
[{"type": "S-8", "sequence": "1", "filename": "k70417sv8.txt", "description": "FORM S-8", "secsgml_size_bytes": 13501}]
{"company-data": {"conformed-name": "SEMCO ENERGY INC", "cik": "0000277158", "assigned-sic": "4924", "irs-number": "382144267", "state-of-incorporation": "MI", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-91406", "film-number": "02690405"}, "business-address": {"street1": "28470 13 MILE ROAD, SUITE 300", "city": "FARMINGTON HILLS", "state": "MI", "zip": "48334", "phone": "248-702-6000"}, "mail-address": {"street1": "28470 13 MILE ROAD, SUITE 300", "city": "FARMINGTON HILLS", "state": "MI", "zip": "48334"}, "former-company": {"former-conformed-name": "SOUTHEASTERN MICHIGAN GAS ENTERPRISES INC", "date-changed": "19920703"}}
As Filed with the Securities and Exchange Commission on June 28, 2002
                                                         Registration No. 333 --

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933

                           --------------------------

                               SEMCO ENERGY, INC.

               (Exact name of issuer as specified in its charter)

               Michigan                                  38-2144267
     (State or other jurisdiction           (I.R.S. Employer Identification No.)
  of incorporation or organization)

         28470 13 Mile Road, Suite 300, Farmington Hills, Michigan 48334
               (Address of Principal Executive Offices) (Zip Code)

                         SEMCO Energy, Inc. 401(k) Plan
                            (Full title of the plan)

                                Arnold R. Madigan
                       Vice President and General Counsel
                               SEMCO Energy, Inc.
                          28470 13 Mile Road, Suite 300
                        Farmington Hills, Michigan 48334
                     (Name and Address of agent for service)
           Telephone number, including area code, of agent of service:
                                  248-702-6208

                          Copies of Communications to:
                               Verne C. Hampton II
                              Dickinson Wright PLLC
                         500 Woodward Avenue, Suite 4000
                             Detroit, Michigan 48226

                  Approximate date of proposed public offering:
 As soon as practicable after the effective date of this Registration Statement

                         CALCULATION OF REGISTRATION FEE
Proposed Maximum                 Proposed
 Title of Securities        Amount to be         Offering Price Per           Maximum Aggregate            Amount of
   to be Registered          Registered                 Share                   Offering Price          Registration Fee
Common Stock ($1 par        400,000 shs.                $7.80                     $3,120,000                $287.04
value)
*Based upon the market price on June 21, 2002
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.        INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

SEMCO Energy, Inc. (the "Company") hereby incorporates by reference in this
Registration Statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission") under the Securities
Exchange Act of 1934, as amended (the "Exchange Act"):

                  1.       The Company's Annual Report on Form 10-K for the year
ended December 31, 2001.

                  2.       The Company's Quarterly Report on Form 10-Q for the
quarter ended March 31, 2002.

                  3.       The description of the Common Stock, $1.00 par value,
of the Company set forth in the Prospectus of the Company dated July 24, 1998
which was part of Amendment No. 1 to Registration Statement No. 333-58715.

All documents subsequently filed with the Commission by the Company pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold shall be
deemed to be incorporated herein by reference and to be a part hereof from the
dates of filing of such documents.

ITEM 4.        DESCRIPTION OF SECURITIES

Not Applicable.

ITEM 5.        INTEREST OF NAMED EXPERTS AND COUNSEL

Not Applicable.

ITEM 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS

The Company's Bylaws and the Michigan Business Corporation Act permit the
Company's officers and directors to be indemnified under certain circumstances
for expenses and in some instances, for judgments, fines or amounts paid in
settlement of civil, criminal, administrative and investigative suits or
proceedings, including those involving alleged violations of the Securities Act
of 1933, as amended (the "Act"). In addition, the Company maintains directors'
and officers' liability insurance which, under certain circumstances, would
cover alleged violation of the Act. Insofar as indemnification for liabilities
arising under the Act may be permitted to officers and directors pursuant to the
foregoing provisions, the Company has been informed that, in the opinion of the
Securities and Exchange Commission, such indemnification is against public
policy as expressed in the Act and is, therefore, unenforceable. Therefore in
the event that a claim for such indemnification is asserted by any officer or
director, the Company (except insofar as such claim seeks reimbursement by the
Company of the expenses paid or incurred by an officer or director in the
successful defense of any action, suit or proceeding) will, unless the matter
has heretofore been adjudicated by precedent deemed by the Company to be
controlling, submit to a court of appropriate jurisdiction the question of
whether or not the indemnification by it is against public policy as expressed
in the Act and will be governed by the final adjudication of such issue.

ITEM 7.        EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable.

                                      -1-
ITEM 8.        EXHIBITS

The following exhibit is filed herewith:

         Exhibit
         Number            Exhibit

           5               Opinion and consent of Dickinson Wright PLLC

The undersigned Company will submit the amended SEMCO Energy, Inc. 401(k) Plan
to the Internal Revenue Service ("IRS") in a timely manner to assure compliance
with the requirements of ERISA and will make all changes required by the IRS in
order to qualify the Plan.

ITEM 9.        UNDERTAKINGS

The undersigned Company hereby undertakes: 1. To file, during any period in
which offers or sales are being made, a post-effective amendment to this
Registration Statement: (i) to include any Prospectus required by Section 10(a)
(3) of the Securities Act of 1933; (ii) to reflect in the Prospectus any facts
or events arising after the effective date of the Registration Statement (or the
most recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in the
Registration Statement; (iii) to include any material information with respect
to the plan of distribution not previously disclosed in the Registration
Statement or any material change to such information in the Registration
Statement; provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
apply if the information required to be included in a post-effective amendment
by those paragraphs is contained in periodic reports filed by the Company
pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934
that are incorporated by reference in the Registration Statement. (2) That, for
purposes of determining any liability under the Securities Act of 1933, each
such post-effective amendment shall be deemed to be a new Registration Statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof. (3)
To remove from registration by means of a post-effective amendment any of the
securities being registered which remain unsold at the termination of the
offering.

The undersigned Company hereby undertakes that, for purposes of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act
of 1934 that is incorporated by reference in the Registration Statement shall be
deemed to be a new Registration Statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act of
1933 may be permitted to directors, officers and controlling persons of the
Company pursuant to the foregoing provisions, or otherwise, the Company has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Company of expenses incurred or
paid by a director, officer or controlling person of the Company, in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question of whether or not such indemnification by it is
against public policy as expressed in the Act and will be governed by the final
adjudication of such issue.

                                      -2-
SIGNATURES

               Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement or amendment thereto to be signed on its behalf by the undersigned,
thereunto duly authorized, in the City of Farmington Hills and State of Michigan
on June 20, 2002.

                                SEMCO ENERGY, INC.

                                      By    /s/ Marcus Jackson
                                        ----------------------------------------
                                            (Marcus Jackson)
                                            Chairman of the Board, President and
                                            Chief Executive Officer

               Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement or amendment thereto has been signed below by the
following persons in the capacities indicated on June 20, 2002.
SIGNATURE                                              TITLE                             SIGNATURE                      TITLE
/s/ Marcus Jackson               Chairman of the Board,                     /s/ John R. Hinton                Director
         ------------------               President and Chief Executive              -------------------
         (Marcus Jackson)                 Officer (Principal Executive               (John R. Hinton)
                                          Officer) and Director

         /s/ John E. Schneider            Senior Vice President,                     /s/ Harvey I. Klein               Director
         ---------------------            Treasurer and Chief Financial              ------------------
         (John E. Schneider)              Officer (Principal Financial               (Harvey I. Klein)
                                          Officer)

         /s/ John M. Albertine            Director                                   /s/ Frederick S. Moore            Director
         ---------------------                                                       ----------------------
         (John M. Albertine)                                                         (Frederick S. Moore)

         /s/ Edward J. Curtis             Director                                   /s/ Thomas W. Sherman             Director
         --------------------                                                        ---------------------
         (Edward J. Curtis)                                                          (Thomas W. Sherman)

         /s/ John T. Ferris               Director                                   /s/ Edith A. Stotler              Director
         ------------------                                                          --------------------
         (John T. Ferris)                                                            (Edith A. Stotler)

         /s/ Michael O. Frazer            Director                                   /s/ Donald W. Thomason            Director
         ---------------------                                                       ----------------------
         (Michael O. Frazer)                                                         (Donald W. Thomason)
-3-
Exhibit Index

Exhibit
Number                                Exhibit
-------                               -------

    5                           Opinion and consent of Dickinson Wright PLLC