EXHIBIT  21
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                               SEMCO ENERGY, INC.

                              List of Subsidiaries
                         Exhibit 21 to Form 10-K (2002)


As of December 31, 2002, the subsidiaries of SEMCO Energy, Inc. (the Registrant)
were:


- -- Alaska  Pipeline  Company,  an  Alaska  corporation
- -- NORSTAR  Pipeline  Company,  Inc.,  an  Alaska  corporation  (a subsidiary of
Alaska  Pipeline  Company)
- -- Aretech  Information  Services,  Inc.,  a  Michigan  corporation
- -- Hotflame  Gas,  Inc.,  a  Michigan  corporation
- -- Sub-Surface  Resources,  Inc.  (formerly  known as NATCOMM, Inc.), a Michigan
corporation
- -- Flint  Construction  Company,  a  Georgia  corporation  (a  subsidiary  of
Sub-Surface  Resources,  Inc.)
- -- Iowa  Pipeline  Associates,  Inc.,  a  Michigan  corporation (a subsidiary of
Sub-Surface  Resources,  Inc.)
- -- K  &  B  Construction,  Inc.,  a  Kansas  corporation  (a  subsidiary of Iowa
Pipeline  Associates,  Inc.)
- -- KLP  Construction  Co.,  Inc.,  an Illinois corporation (a subsidiary of Iowa
Pipeline  Associates,  Inc.)
- -- Long's  Underground  Technologies, Inc., a Michigan corporation (a subsidiary
of  Sub-Surface  Resources,  Inc.)
- -- Sub-Surface  Construction  Co.,  a  Michigan  corporation  (a  subsidiary  of
Sub-Surface  Resources,  Inc.)
- -- SEMCO  Energy  Ventures,  Inc.,  a  Michigan  corporation
- -- SEMCO  Arkansas  Pipeline  Company,  a  Michigan corporation (a subsidiary of
SEMCO  Energy  Ventures,  Inc.)
- -- SEMCO  Gas  Storage  Company,  a  Michigan corporation (a subsidiary of SEMCO
Energy  Ventures,  Inc.)
- -- SEMCO  Pipeline  Company,  a  Michigan  corporation  (a  subsidiary  of SEMCO
Energy  Ventures,  Inc.)
- -- Southeastern  Development  Company,  a  Michigan corporation (a subsidiary of
SEMCO  Energy  Ventures,  Inc.)
- -- Southeastern  Financial  Services, Inc., a Michigan corporation (a subsidiary
of  SEMCO  Energy  Ventures,  Inc.)


Each  of  the  above-listed  companies  does  business only under its respective
corporate  name  as  indicated  above,  except  as  follows:

- -- SEMCO  Energy,  Inc.  does  business  in Alaska under the name ENSTAR Natural
Gas  Company  and  in  Michigan  as  SEMCO  Energy  Gas  Company.
- -- Aretech  Information  Services, Inc. does business in Michigan under the name
Arenet.net  and  Arenet.
- -- Flint  Construction  Company  does  business  in West Virginia under the name
FCCO,  Inc.
- -- Sub-Surface  Construction  Co.  does  business  in  Ohio  under  the name Sub
Surface  Gas  Services  and  Main  Construction  Co.