<PAGE>   1
                                                                       EXHIBIT 2


                               ARTICLES OF MERGER
                                       OF
                             MBLE MERGER CO., INC.
                                      INTO
                         MOBILE GAS SERVICE CORPORATION


     Pursuant to Section 10-2B-11.05 of the Alabama Business Corporation Act, 
the undersigned corporations, Mobile Gas Service Corporation ("Mobile Gas"), an
Alabama corporation, and MBLE Merger Co., Inc. ("Mergerco"), an Alabama
corporation, adopt the following Articles of Merger for the purpose of merging
Mergerco into Mobile Gas:

     FIRST:    The Amended and Restated Agreement and Plan of Merger setting
forth the terms and conditions of the merger of Mergerco with and into Mobile
Gas (the "Merger Agreement") is attached hereto as Exhibit A and incorporated
herein by reference.

     SECOND:   There are 3,239,104 shares of common stock, par value $.01 per
share, of Mobile Gas ("Mobile Gas Stock") issued and outstanding that were
entitled to vote on the Merger Agreement, such shares being the only voting
group of Mobile Gas entitled to vote on the Merger Agreement.  2,508,700 shares
of Mobile Gas Stock were voted in favor of the Merger Agreement and 9,084
shares of Mobile Gas Stock were voted against the Merger Agreement at the
Annual Meeting of Stockholders of Mobile Gas held on January 30, 1998.

     THIRD:    There are 100 shares of common stock, par value $.01 per
share,of Mergerco ("Mergerco Stock") issued and outstanding that were entitled
to vote on the Merger Agreement, such shares being the only voting group of
Mergerco entitled to vote on the Merger Agreement.  100 shares of Mergerco
Stock were voted in favor of the Merger Agreement, and no shares of Mergerco
Stock were voted against the Merger Agreement, by the sole shareholder of
Mergerco on December 10, 1997.

     FOURTH:   The respective Articles of Incorporation of each of Mobile
Gas and Mergerco are filed in Mobile County, Alabama.

     FIFTH:    These Articles of Merger shall take effect at 12:01 a.m. on
February 2, 1998.
<PAGE>   2

     IN WITNESS WHEREOF, each of the undersigned corporations has caused these
Articles of Merger to be signed as of January 30, 1998.

                              MOBILE GAS SERVICE CORPORATION

                              By: /s/ John S. Davis
                                   John S. Davis
                              Its: President
                                             and

                              By: /s/ G. Edgar Downing, Jr.
                                   G. Edgar Downing, Jr.
                              Its: Secretary


                              MBLE MERGER CO., INC.

                              By: /s/ John S. Davis
                                   John S. Davis
                              Its: President
                                             and

                              By: /s/ G. Edgar Downing, Jr.
                                   G. Edgar Downing, Jr.
                              Its: Secretary
<PAGE>   3
Exhibit A

                              AMENDED AND RESTATED
                          AGREEMENT AND PLAN OF MERGER

THIS AMENDED AND RESTATED AGREEMENT AND PLAN OF MERGER ("Agreement"), dated as
of January 29, 1998, amends and restates the Agreement and Plan of Merger is
made as of December 10, 1997, by and among MOBILE GAS SERVICE CORPORATION, an
Alabama corporation ("Mobile Gas"), MBLE MERGERCO., INC., an Alabama
corporation ("Mergerco"), and ENERGYSOUTH, INC., an Alabama corporation
("EnergySouth").

     WHEREAS, Mobile Gas has authorized capital stock consisting of 8,000,000
shares of common stock, one cent ($.01) par value per share ("Mobile Gas Common
Stock"), of which 3,239,104 shares are issued and outstanding; and

     WHEREAS, Mergerco has authorized capital stock consisting of 1,000 shares
of common stock ("Mergerco Common Stock"), of which 100 shares are issued and
outstanding and owned beneficially and of record by EnergySouth; and

     WHEREAS, EnergySouth has authorized capital stock consisting of 10,000,000
shares of common stock, one cent ($.01) par value per share ("EnergySouth
Common Stock"), of which 100 shares are issued and outstanding and owned
beneficially and of record by Mobile Gas, and 10,000,000 shares of Preferred
Stock, no par value per share, none of which have been issued; and

     WHEREAS, the Boards of Directors of the respective parties hereto deem it
advisable to merge Mergerco with and into Mobile Gas in accordance with the
Alabama Business Corporation Act ("Alabama Corporation Act") and this Agreement
for the purpose of establishing EnergySouth as the parent corporation of Mobile
Gas.

     NOW, THEREFORE, in consideration of the premises and agreements contained
herein, the parties agree that (i) Mergerco shall be merged with and into
Mobile Gas (the "Merger"), (ii) Mobile Gas shall be the corporation surviving
the Merger, and (iii) the terms and conditions of the Merger, the mode of
carrying it into effect, the manner of converting and exchanging shares of
capital stock of the parties hereto and other matters relating thereto shall be
as follows:

                                  ARTICLE 1
                                 THE MERGER

     1.1  Articles of Merger.  Subject to and in accordance with the provisions
of this Agreement, in the event this Agreement and Plan of Merger is approved
by the stockholders of Mobile Gas in accordance



                                     A-1
<PAGE>   4
with the Alabama Corporation Act, Articles of Merger of Mobile Gas shall
be delivered to the office of the Secretary of State of Alabama for filing, all
as provided in Section 10-2B-11.05 of the Alabama Corporation Act.

     1.2  Effective Time.  The Merger shall become effective at the time of
filing on the date on which the Articles of Merger are filed with the Secretary
of State of Alabama as contemplated by Section 1.1 above, unless otherwise
specified in such Articles of Merger (the "Effective Time").  At the Effective
Time, the separate existence of Mergerco shall cease and Mergerco shall be
merged with and into Mobile Gas, which shall continue its corporate existence
as the surviving corporation (Mobile Gas and Mergerco being sometimes referred
to herein as the "Constituent Corporations" and Mobile Gas, as the surviving
corporation, being sometimes referred to herein as the "Surviving
Corporation").  Mobile Gas shall succeed, without other transfer, to all the
rights and property of Mergerco and shall be subject to all the debts and
liabilities of Mergerco in the same manner as if Mobile Gas had itself incurred
them. All rights of creditors and all liens upon the property of each of Mobile
Gas and Mergerco shall be preserved unimpaired.

     1.3  Appropriate Actions.  Prior to and after the Effective Time,
EnergySouth, Mobile Gas and Mergerco, respectively, shall take all such actions
as may be necessary or appropriate in order to effectuate the Merger.  In this
connection, EnergySouth shall issue and pay the shares of EnergySouth Common
Stock and cash in lieu of fractional shares into which outstanding shares of
Mobile Gas Common Stock will be converted on the basis and to the extent
provided in Article 2 of this Agreement, and shall take such other actions as
are necessary to fulfil EnergySouth's obligations hereunder including without
limitation those specified in Article 6 of this Agreement.  In case at any time
after the Effective Time any further action is necessary or desirable to carry
out the purposes of this Agreement and to vest the Surviving Corporation with
full title to all properties, assets, privileges, rights, immunities and
franchises of either of the Constituent Corporations, the officers and
directors of each of the Constituent Corporations as of the Effective Time
shall take all such further action.


                                   ARTICLE 2
                   TERMS OF CONVERSION AND EXCHANGE OF SHARES

     2.1  Mobile Gas Common Stock.  (a)  At the Effective Time, subject to
subsection (b) below, shares of Mobile Gas Common Stock issued and outstanding
immediately prior to the Merger shall be automatically changed and converted
into shares of EnergySouth Common Stock, at the ratio of three shares of
EnergySouth Common Stock for each two shares of Mobile Gas Common Stock, and
such EnergySouth Common Stock shall thereupon be issued and fully-paid and
non-assessable; provided, however, that such conversion shall not affect shares
of holders, if any, who perfect their rights as dissenting stockholders under
Article 13 of the Alabama Corporation Act with respect to such shares.

     (b)  No scrip or certificates representing fractional shares of
EnergySouth Common Stock shall



                                     A-2
<PAGE>   5
be issued to any former stockholder of Mobile Gas, and, except as provided
below, no such stockholder shall have any right to vote or receive any dividend
or other distribution on, or any other right with respect to, any fraction of a
share of EnergySouth Common Stock resulting from the conversion described in
Section 2.1. In the event such conversion of shares results in the creation of
fractional shares, in lieu of the issuance of fractional shares of EnergySouth
Common Stock, EnergySouth shall deliver cash to the transfer agent for
EnergySouth Stock (the "Transfer Agent") in an amount equal to the aggregate of
all fractional shares multiplied by the Average Closing Price, and, in such
event, the Transfer Agent shall divide such cash among and remit it (without
interest) to the former stockholders of Mobile Gas in accordance with their
respective interests.  The "Average Closing Price" shall be two-thirds the
average of the closing prices of Mobile Gas Common Stock on the Nasdaq National
Market over the period of five (5) consecutive trading days ending on the last
trading day prior to the Effective Date.

     2.2  Mergerco Shares.  The shares of Mergerco Common Stock issued and
outstanding immediately prior to the Merger shall be automatically changed and
converted into all of the issued and outstanding shares of Common Stock of the
Surviving Corporation, which shall thereupon be issued and fully-paid and
non-assessable, with the effect that the number of issued and outstanding
shares of Common Stock of the Surviving Corporation shall be the same as the
number of issued and outstanding shares of Mergerco Common Stock immediately
prior to the Effective Time.

     2.3  EnergySouth Shares.  Each share of EnergySouth Common Stock issued
and outstanding immediately prior to the Merger shall be canceled.

                                   ARTICLE 3
                      ARTICLES OF INCORPORATION AND BYLAWS

     3.1  Mobile Gas Restated Articles. From and after the Effective Time, and
until thereafter amended as provided by law, the Restated Articles of
Incorporation of Mobile Gas as in effect immediately prior to the Merger shall
be and continue to be the Restated Articles of Incorporation of the Surviving
Corporation.

     3.2  Mobile Gas By-Laws.  From and after the Effective Time, and until
thereafter amended as provided by law, the By-Laws of Mobile Gas as in effect
immediately prior to the Merger shall be and continue to be the By-Laws of the
Surviving Corporation.

     3.3  EnergySouth Articles and Bylaws.  From and after the Effective Time,
and until thereafter amended as provided by law, the Articles of Incorporation
and Bylaws of EnergySouth as in effect immediately prior to the Merger shall be
and continue unchanged to be the Articles of Incorporation and By-Laws of
EnergySouth.



                                     A-3
<PAGE>   6
                                   ARTICLE 4
                             DIRECTORS AND OFFICERS

     4.1  Mobile Gas Directors and Officers.  The persons who are directors and
officers of Mobile Gas immediately prior to the Merger shall continue as
directors and officers, respectively, of the Surviving Corporation and shall
continue to hold office as provided in the Bylaws of the Surviving Corporation.
If, at or following the Effective Time, a vacancy shall exist in the Board of
Directors or in the position of any officer of the Surviving Corporation, such
vacancy may be filled in the manner provided in the Bylaws of the Surviving
Corporation.

     4.2  EnergySouth Directors and Officers.  The persons who are directors
and officers of EnergySouth immediately prior to the Merger shall continue as
directors and officers, respectively, of EnergySouth and shall continue to hold
office as provided in the Bylaws of EnergySouth.  If, at or following the
Effective Time, a vacancy shall exist in the Board of Directors or in the
position of any officer of EnergySouth, such vacancy shall be filled in the
manner provided in the Bylaws of EnergySouth.

                                   ARTICLE 5
                               STOCK CERTIFICATES

     5.1  Rights of Holders of Certificates. Following the Effective Time,
certificates representing shares of Mobile Gas Common Stock outstanding at the
Effective Time (herein sometimes referred to as "Mobile Gas Certificates")
shall evidence only the right of the registered holder thereof to receive, and
may be exchanged for, the shares of EnergySouth Common Stock into which such
shares of Mobile Gas Common Stock were converted in accordance with Section
2.1. At the Effective Time, EnergySouth shall issue and deliver, or cause to be
issued and delivered, to the Transfer Agent certificates representing whole
shares of EnergySouth Stock into which outstanding shares of Mobile Gas Stock
have been converted as provided above. As promptly as practicable following the
Effective Time, EnergySouth shall send or cause to be sent to each former
stockholder of record of Mobile Gas immediately prior to the Effective Time
written instructions and transmittal materials (a "Transmittal Letter") for use
in surrendering Mobile Gas Certificates to the Transfer Agent. Upon the proper
surrender and delivery to the Transfer Agent (in accordance with EnergySouth's
instructions, and accompanied by a properly completed Transmittal Letter) by a
former stockholder of Mobile Gas of such stockholder's Mobile Gas 
Certificate(s), and in exchange therefor, the Transfer Agent shall as soon as
practicable, (i) in the case of a stockholder whose Mobile Gas Common Stock, or
a portion thereof, has been converted into EnergySouth Stock, issue, register
and deliver to such stockholder a certificate evidencing the number of shares
of EnergySouth Stock to which such stockholder is entitled pursuant to Section
2.1 above, and/or (ii) in the case of a stockholder whose Mobile Gas Common
Stock, or a portion thereof, has been converted into the right to receive cash
in lieu of a fractional share, issue and deliver to such stockholder a check in
the amount of cash to which the stockholder is entitled pursuant to Section 2.1
above.



                                     A-4
<PAGE>   7
     5.2  Outstanding Certificates.  Each outstanding certificate which, prior
to the Effective Time, represented Mobile Gas Common Stock shall be deemed for
all corporate purposes to represent only the right to receive the number of
shares of EnergySouth Common Stock and/or cash in lieu of fractional shares
into which such Mobile Gas Common Stock was converted.

     5.3  Stock Transfer Books.  The stock transfer books for Mobile Gas Common
Stock shall be deemed to be closed at the Effective Time and no transfer of
shares of Mobile Gas Common Stock outstanding prior to the Effective Time shall
thereafter be made on such books.  As of the Effective Time, EnergySouth shall
establish a stock register reflecting ownership of EnergySouth Common Stock by
former holders of record of Mobile Gas Common Stock.

     5.4  Post-Merger Rights of Holders.  Following the Effective Time, the
holders of certificates representing Mobile Gas Common Stock outstanding
immediately prior to the Effective Time shall cease to have any rights with
respect to stock of the Surviving Corporation and their sole rights shall be
with respect to the EnergySouth Common Stock and/or cash in lieu of fractional
shares into which their shares of Mobile Gas Common Stock shall have been
converted by the Merger, subject to the rights of any dissenting stockholders
who perfect dissenters' rights under Article 13 of the Alabama Corporation Act.

     5.5  Unsurrendered Certificates. Subject to Section 5.6 below, no 
EnergySouth Common Stock certificate or cash in lieu of a fractional share
thereof shall be delivered to any former stockholder of Mobile Gas unless and
until such stockholder shall have properly surrendered to the Transfer Agent the
Mobile Gas Certificate(s) formerly representing his or her shares of Mobile Gas
Stock, together with a properly completed Transmittal Letter in such form as
shall be provided to the stockholder by EnergySouth for that purpose. Further,
until such Mobile Gas Certificate(s) are so surrendered, no dividend or other
distribution payable to holders of record of EnergySouth Stock as of any date 
subsequent to the Effective Time shall be delivered to the holder of such 
Mobile Gas Certificate(s). However, subject to prior escheatment under
applicable law, upon the proper surrender of such Mobile Gas Certificate(s),
the Transfer Agent shall pay to the registered holder of the shares of
EnergySouth Stock represented by such Mobile Gas Certificate(s) the amount of
any such cash, dividends or distributions which have accrued but remain unpaid
with respect to such shares.  Neither EnergySouth, Mobile Gas nor the Transfer
Agent shall have any obligation to pay any interest on any such cash, dividends
or distributions for any period prior to such payment.

     5.6  Lost, etc., Certificates.  Any stockholder of Mobile Gas
whose certificate evidencing shares of Mobile Gas Common Stock has been
lost, destroyed, stolen or otherwise is missing shall be entitled to receive a
certificate representing the shares of EnergySouth Common Stock to which he or
she is entitled in accordance with and upon compliance with conditions imposed
by the Transfer Agent or EnergySouth (including without limitation a requirement
that the stockholder provide a lost instruments indemnity or surety bond in
form, substance and amount satisfactory to the Transfer Agent and EnergySouth).



                                     A-5
<PAGE>   8
                                  ARTICLE 6
                           MOBILE GAS STOCK PLANS

     Mobile Gas and EnergySouth shall take all actions required to provide that,
from and after the Effective time or as soon as practicable thereafter, the
following Mobile Gas plans shall utilize EnergySouth Common Stock instead of
Mobile Gas Common Stock and shall include, where appropriate "EnergySouth" in
the name and text of each such plan:  (i) the Employee Savings Plans; (ii) the
Mobile Gas Service Corporation 1992 Stock Option Plan; (iii) the Mobile Gas
Service Corporation Incentive Compensation Plan; and (iv) the Mobile Gas Service
Corporation Dividend Reinvestment and Stock Purchase Plan.

                                   ARTICLE 7
                            CONDITIONS OF THE MERGER

     Completion of the Merger is subject to the satisfaction of the following
conditions:

     6.1  Stockholder Approval.  The principal terms of this Agreement shall
have been approved by such holders of capital stock of each of the Constituent
Corporations as is required by the Alabama Corporation Act.     

     6.2  EnergySouth Common Stock Listed.  All conditions for the listing on 
the NASDAQ National Market as of the Effective Time of the EnergySouth Common 
Stock to be issued and to be reserved for issuance pursuant to the Merger shall
have been satisfied.

     6.3  Restated Articles of EnergySouth.  Restated Articles of Incorporation
of EnergySouth, substantially in the form appended hereto as Exhibit A, shall
have been adopted by EnergySouth and remain in effect.

     6.4  Regulatory Approvals.  All necessary orders, authorization, approvals
or waivers from the PSC and all other jurisdiction regulatory bodies, boards or
agencies shall have been received, remain in full force and effect, and shall
not include, in the sole judgment of the Board of Directors of Mobile Gas,
unacceptable conditions.


                                   ARTICLE 8
                           AMENDMENT AND TERMINATION

     7.1  Amendment.  The parties to this Agreement, by mutual consent of their
respective boards of directors, may amend, modify or supplement this Agreement
in such manner as may be agreed upon by them in writing at any time before or
after approval of this Agreement by the pre-Merger stockholders of



                                     A-6
<PAGE>   9
Mobile Gas (as provided in Section 6.1 above); provided, however, that no such
amendment, modification or supplement shall, if agreed to after such approval by
the pre-Merger stockholders of Mobile Gas, change any of the principal terms of
this Agreement in a manner which would materially and adversely affect the
rights of the stockholders of Mobile Gas.

     7.2  Termination.  This Agreement may be terminated and the Merger and
other transactions provided for by this Agreement may be abandoned at any time,
whether before or after approval of this Agreement by the pre-Merger
stockholders of Mobile Gas, by action of the board of directors of Mobile Gas if
such board of directors determines for any reason that the completion of the
transactions provided for herein would for any reason be inadvisable or not in
the best interests of Mobile Gas or its stockholders.


                                   ARTICLE 9
                                 MISCELLANEOUS

     8.1  Counterparts.  This Agreement may be executed in multiple 
counterparts, each of which shall be deemed an original hereof.

     8.2  Alabama Law.  This Agreement shall be governed by and interpreted in
accordance with the laws of the State of Alabama.

     IN WITNESS WHEREOF, Mobile Gas, EnergySouth and Mergerco, pursuant to
approval and authorization duly given by resolutions adopted by the irrespective
boards of directors, have each caused this Agreement to be executed by its
President or one of its Vice Presidents and attested by its Secretary or one of
its Assistant Secretaries.

                                   Mobile Gas:
                                        MOBILE GAS SERVICE CORPORATION,
                                        an Alabama corporation

                                   By:     /s/ John S. Davis
                                        Its:  President and Chief Executive
                                        Officer
           Attest:
By: /s/  G. Edgar Downing, Jr.
Its:  Secretary




                                     A-7
<PAGE>   10
                                   EnergySouth:
                                        ENERGYSOUTH, INC.,
                                        an Alabama corporation

                                        By:     /s/ John S. Davis
                                   Its:  President and Chief Executive
                                   Officer

              Attest:
By:    /s/ G. Edgar Downing, Jr.
Its:  Secretary

                                   Mergerco:
                                   MBLE MERGER CO., INC.,
                                   an Alabama corporation

                                   By:     /s/ John S. Davis
                                   Its:  President and Chief Executive
                                        Officer
               Attest:
By:    /s/ G. Edgar Downing, Jr.
Its:  Secretary




                                     A-8