<PAGE 1>


               UNITED STATES SECURITIES AND EXCHANGE COMMISSION

                         Washington, D. C. 20549-1004


                                   FORM 10-Q


(Mark One)

[ X ] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934

      For the quarterly period ended June 30, 1998

                                      OR

[   ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934

      For the Transition Period from ________________ to ________________

                         Commission File Number 1-7316

                            COMMONWEALTH ENERGY SYSTEM                   
      (Exact name of registrant as specified in its Declaration of Trust)

              Massachusetts                                  04-1662010  
      (State or other jurisdiction of                    (I.R.S. Employer
      incorporation or organization)                     Identification No.)


      One Main Street, Cambridge, Massachusetts              02142-9150    
      (Address of principal executive offices)               (Zip Code)


      Registrant's telephone number, including area code   (617) 225-4000  

                                                                         
      (Former name, address and fiscal year, if changed since last report)

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to
such filing requirements for the past 90 days.       YES   X    NO       

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of the latest practicable date.

                                                    Outstanding at
         Class of Common Stock                      August 1, 1998  

      Common Shares of Beneficial
      Interest, $2 par value                       21,533,820 shares

<PAGE 2>


                        PART I. - FINANCIAL INFORMATION

Item 1.  Financial Statements

                          COMMONWEALTH ENERGY SYSTEM

                     CONSOLIDATED CONDENSED BALANCE SHEETS

                      JUNE 30, 1998 AND DECEMBER 31, 1997

                                    ASSETS

                            (Dollars in thousands)


                                                     June 30,    December 31, 
                                                       1998          1997     
                                                    (Unaudited)

PROPERTY, PLANT AND EQUIPMENT, at original cost
  Electric                                          $1,185,822   $1,173,797
  Gas                                                  379,204      373,541
  Other                                                119,573       72,475
                                                     1,684,599    1,619,813
  Less - Accumulated depreciation and
           amortization                                608,659      577,962
                                                     1,075,940    1,041,851
  Add - Construction work in progress
          and nuclear fuel in process                   11,558        8,057
                                                     1,087,498    1,049,908

EQUITY IN CORPORATE JOINT VENTURES
  Nuclear electric power companies (2.5%
     to 4.5%)                                           10,959       10,368
  Other investments                                      3,232        3,399
                                                        14,191       13,767

CURRENT ASSETS
  Cash                                                   2,144        4,299
  Accounts receivable                                  103,664      128,946
  Unbilled revenues                                      8,185       32,029
  Inventories, at average cost                          30,238       32,644
  Prepaid taxes and other                                8,534       15,068
                                                       152,765      212,986

DEFERRED CHARGES
  Regulatory assets                                    200,996      178,864
  Other                                                 60,731       29,525
                                                       261,727      208,389

                                                    $1,516,181   $1,485,050



                            See accompanying notes.

<PAGE 3>

                          COMMONWEALTH ENERGY SYSTEM

                     CONSOLIDATED CONDENSED BALANCE SHEETS

                      JUNE 30, 1998 AND DECEMBER 31, 1997

                        CAPITALIZATION AND LIABILITIES

                            (Dollars in thousands)

                                                     June 30,  December 31,
                                                       1998        1997    
                                                    (Unaudited)
CAPITALIZATION
  Common share investment -
    Common shares, $2 par value -
      Authorized - 50,000,000 shares
      Outstanding - 21,533,820 in 1998 and
        21,531,784 in 1997                          $   43,068   $   43,063
    Amounts paid in excess of par value                112,043      111,912
    Retained earnings                                  284,480      275,795
                                                       439,591      430,770
  Redeemable preferred shares, less current
    sinking fund requirements                           11,950       12,200
  Long-term debt, including premiums, less current
    sinking fund requirements and maturing debt        343,164      364,311
                                                       794,705      807,281

CAPITAL LEASE OBLIGATIONS                               11,322       12,272

CURRENT LIABILITIES
  Interim Financing - 
    Notes payable to banks                             226,625       94,075
    Maturing long-term debt                             29,000       19,000
                                                       255,625      113,075

  Other Current Liabilities -
    Current sinking fund requirements                    8,473        8,473
    Accounts payable                                    75,228      107,157
    Accrued taxes                                        4,109       24,205
    Other                                               80,039       58,922
                                                       167,849      198,757
                                                       423,474      311,832

DEFERRED CREDITS
  Accumulated deferred income taxes                    114,066      176,354
  Nuclear units' purchased power contracts              64,520       69,659
  Unamortized investment tax credits
     and other                                         108,094      107,652
                                                       286,680      353,665

COMMITMENTS AND CONTINGENCIES

                                                    $1,516,181   $1,485,050

                            See accompanying notes.

<PAGE 4>


                          COMMONWEALTH ENERGY SYSTEM

                  CONSOLIDATED CONDENSED STATEMENTS OF INCOME

           FOR THE THREE AND SIX MONTHS ENDED JUNE 30, 1998 AND 1997

          (Dollars in thousands except per share amounts - unaudited)

                                   Three Months Ended      Six Months Ended 
                                    1998        1997       1998        1997
OPERATING REVENUES
  Electric                         $139,393   $157,251    $295,197   $334,055
  Gas                                58,235     60,930     173,374    193,197
  Steam and other                     6,663      3,763      12,324     10,882
                                    204,291    221,944     480,895    538,134

OPERATING EXPENSES
  Fuel and purchased power           69,398     85,786     156,006    192,045
  Cost of gas sold                   35,526     30,627      90,903    102,737
  Other operation and maintenance    66,244     79,593     124,734    140,187
  Depreciation                       14,377     12,808      30,556     28,320
  Taxes -
    Federal and state income            912     (1,280)     17,018     15,394
    Local property and other          6,288      6,617      15,078     15,776
                                    192,745    214,151     434,295    494,449

OPERATING INCOME                     11,546      7,793      46,600     43,685

OTHER INCOME                            804        981       1,499      1,630

INCOME BEFORE INTEREST CHARGES       12,350      8,774      48,099     45,315

INTEREST CHARGES
  Long-term debt                      8,703      8,385      17,220     16,789
  Other interest charges              2,678      1,813       4,445      3,618
  Allowance for borrowed funds
    used during construction            (96)       (90)       (200)      (158)
                                     11,285     10,108      21,475     20,249
NET INCOME (LOSS)                     1,065     (1,334)     26,624     25,066
  Dividends on preferred shares         237        251         474        503
EARNINGS (LOSS) APPLICABLE
  TO COMMON SHARES                 $    828   $ (1,585)   $ 26,150   $ 24,563
AVERAGE NUMBER OF COMMON
  SHARES OUTSTANDING             21,533,820 21,531,784  21,533,141 21,530,144

BASIC AND DILUTED EARNINGS
  (LOSS) PER COMMON SHARE             $ .03      $(.07)      $1.21      $1.14
DIVIDENDS DECLARED PER
  COMMON SHARE                        $.405      $.395       $.405      $.395





                            See accompanying notes.

<PAGE 5>


                          COMMONWEALTH ENERGY SYSTEM

                CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS

                FOR THE SIX MONTHS ENDED JUNE 30, 1998 AND 1997

                      (Dollars in thousands - unaudited)

                                                       1998          1997


OPERATING ACTIVITIES
  Net income                                        $ 26,624       $ 25,066
  Effects of noncash items -
    Depreciation and amortization                     36,447         35,267
    Deferred income taxes and investment
      tax credits, net                                   198         (1,283)
    Earnings from corporate joint ventures              (852)          (870)
  Dividends from corporate joint ventures                277            382
  Change in working capital, exclusive of cash
    and interim financing                             27,637         35,763
  Transition costs deferral                          (30,246)           -  
  All other operating items                            6,952        (10,978)
Net cash provided by operating activities             67,037         83,347

INVESTING ACTIVITIES
  Purchase of total energy plant
    and related contracts                           (146,270)           -  
  Additions to property, plant and equipment
    (inclusive of AFUDC) -
      Electric                                       (15,462)       (12,938)
      Gas                                             (7,428)        (6,790)
      Other                                           (3,246)          (921)
Net cash used for investing activities              (172,406)       (20,649)

FINANCING ACTIVITIES
  Payment of dividends                               (17,939)       (17,537)
  Proceeds from (payment of) short-term borrowings   132,550        (26,650)
  Long-term debt issue refunded                      (10,000)       (14,260)
  Sinking funds payments                              (1,397)        (1,398)
Net cash provided by (used for)
  financing activities                               103,214        (59,845)
Net increase (decrease) in cash                       (2,155)         2,853
Cash at beginning of period                            4,299          1,495
Cash at end of period                               $  2,144       $  4,348

SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
  Cash paid during the period for:
    Interest (net of capitalized amounts)           $ 19,544       $ 19,550
    Income taxes                                    $ 22,130       $ 16,933




                            See accompanying notes.

<PAGE 6>


                          COMMONWEALTH ENERGY SYSTEM
             NOTES TO CONSOLIDATED CONDENSED FINANCIAL STATEMENTS

(1) General Information

        Commonwealth Energy System, the parent company, is referred to in this
    report as the "System" and, together with its subsidiaries, is collec-
    tively referred to as "the system."  The System is an exempt public
    utility holding company under the provisions of the Public Utility Holding
    Company Act of 1935 with investments in four operating public utility
    companies located in central, eastern and southeastern Massachusetts.  In
    addition, the System has interests in other utility and several non-
    regulated companies.

        The system has 1,792 regular employees including 1,142 (64%)
    represented by various collective bargaining units.  One of these collec-
    tive bargaining units, representing approximately 5% of regular employees,
    recently reached an agreement on a new five-year contract that remains in
    effect until April 30, 2003.  Upon expiration of another contract
    (representing approximately 5% of regular employees) scheduled to expire
    on September 1, 1998, a new agreement, which has already been ratified,
    will become effective through March 1, 2001.  A third agreement
    (representing 2% of regular employees) is scheduled to expire in September
    1998.

    Accounting Policies

    (a) Principles of Accounting

        The system's significant accounting policies are described in Note 2
    of Notes to Consolidated Financial Statements included in its 1997 Annual
    Report on Form 10-K filed with the Securities and Exchange Commission. 
    For interim reporting purposes, the system follows these same basic
    accounting policies but considers each interim period as an integral part
    of an annual period and makes allocations of certain expenses to interim
    periods based upon estimates of such expenses for the year.

        Generally, certain expenses which relate to more than one interim
    period are allocated to other periods to more appropriately match revenues
    and expenses.  Principal items of expense which are allocated other than
    on the basis of passage of time are depreciation and property taxes of the
    gas subsidiary, Commonwealth Gas Company (Commonwealth Gas).  These
    expenses are recorded for interim reporting purposes based upon projected
    gas revenue.  Income tax expense is recorded using the statutory rates in
    effect applied to book income subject to tax for each interim period.

        The unaudited financial statements for the periods ended June 30, 1998
    and 1997, reflect, in the opinion of the System, all adjustments
    (consisting of only normal recurring accruals, except for a one-time
    charge recorded in June 1997 as described in Management's Discussion and
    Analysis of Financial Condition and Results of Operations) necessary to
    summarize fairly the results for such periods.  In addition, certain

<PAGE 7>

                          COMMONWEALTH ENERGY SYSTEM

    prior period amounts are reclassified from time to time to conform with
    the presentation used in the current period's financial statements.

        The results for interim periods are not necessarily indicative of
    results for the entire year because of seasonal variations in the
    consumption of energy and Commonwealth Gas' seasonal rate structure.

    (b) Regulatory Assets and Liabilities

        The system's operating utility companies are regulated as to rates,
    accounting and other matters by various authorities, including the Federal
    Energy Regulatory Commission (FERC) and the Massachusetts Department of
    Telecommunications and Energy (DTE).

        Based on the current regulatory framework, the system accounts for the
    economic effects of regulation in accordance with the provisions of
    Statement of Financial Accounting Standards (SFAS) No. 71, "Accounting for
    the Effects of Certain Types of Regulation."  Regulated subsidiaries of
    the System have established various regulatory assets in cases where the
    DTE and/or the FERC have permitted or are expected to permit recovery of
    specific costs over time.  Similarly, the regulatory liabilities
    established by the system are required to be refunded to customers over
    time.  In the event the criteria for applying SFAS No. 71 are no longer
    met, the accounting impact would be an extraordinary, non-cash charge to
    operations of an amount that could be material.  Criteria that give rise
    to the discontinuance of SFAS No. 71 include: 1) increasing competition
    that restricts the system's ability to establish prices to recover
    specific costs, and 2) a significant change in the current manner in which
    rates are set by regulators from cost based regulation to another form of
    regulation.  These criteria are reviewed on a regular basis to ensure the
    continuing application of SFAS No. 71 is appropriate.  Based on the
    current evaluation of the various factors and conditions that are expected
    to impact future cost recovery, the system believes that its regulatory
    assets, including those related to generation, are probable of future
    recovery.

        As a result of electric industry restructuring, the system's retail
    electric companies discontinued application of accounting principles
    applied to their investment in electric generation facilities effective
    March 1, 1998.  The system will not be required to write off any of its
    generation-related assets, including regulatory assets.  These assets will
    be retained on the Consolidated Condensed Balance Sheets because the
    legislation and the DTE's plan for a restructured electric industry
    specifically provide for their recovery through a non-bypassable
    transition charge.










<PAGE 8>

                          COMMONWEALTH ENERGY SYSTEM

        The principal regulatory assets included in deferred charges were as
    follows:

                                                       June 30,   December 31,
                                                         1998        1997
                                                      (Dollars in thousands)

      Maine Yankee unrecovered plant and
         decommissioning costs                         $ 32,595    $ 34,908
      Transition costs                                   30,554         -  
      Fuel charge stabilization                          27,885      29,655
      Connecticut Yankee unrecovered plant and
         decommissioning costs                           26,839      28,566
      Postretirement benefits costs                      24,867      25,475
      Power contract buy-out                             16,515      17,609
      Deferred income taxes                              13,171      13,089
      FERC Order 636 transition costs                     6,652       7,336
      Environmental costs                                 5,548       3,930
      Yankee Atomic unrecovered plant and
         decommissioning costs                            5,086       6,184
      Seabrook related costs                              3,670       4,324
      Other                                               7,614       7,788
                                                       $200,996    $178,864

         The regulatory liabilities, reflected in deferred credits in the
    accompanying Consolidated Condensed Balance Sheets and related primarily
    to deferred income taxes, were $13.5 million and $14.1 million at June 30,
    1998 and December 31, 1997, respectively.

         In November 1997, the Commonwealth of Massachusetts enacted a
    comprehensive electric utility industry restructuring bill.  On November
    19, 1997, the System's electric subsidiaries filed a restructuring plan
    with the DTE.  The plan, approved by the DTE on February 27, 1998,
    provides that the System's retail electric subsidiaries, beginning March
    1, 1998, initiate a ten percent rate reduction for all customer classes
    and allow customers to choose their energy supplier.  As part of the plan,
    the DTE authorized the recovery of certain strandable costs and provides
    that certain future costs may be deferred to achieve or maintain the rate
    reductions that the restructuring bill mandates.  The legislation gives
    the DTE the authority to determine the amount of strandable costs that
    will be eligible for recovery.  Costs that will qualify as strandable
    costs and be eligible for recovery include, but are not limited to,
    certain above market costs associated with generating facilities, costs
    associated with long-term commitments to purchase power at above market
    prices from independent power producers and regulatory assets and
    associated liabilities related to the generation portion of the electric
    business.

         The cost of transitioning to competition will be mitigated, in part,
    by the sale of the system's non-nuclear generating assets.  The sale is
    expected to be completed by year-end 1998 pending receipt of the necessary
    regulatory approvals.  The net proceeds from the sale of these assets will
    be used to mitigate transition costs.

<PAGE 9>

                          COMMONWEALTH ENERGY SYSTEM

         The system's ability to recover its transition costs will depend on
    several factors, including the aggregate amount of transition costs the
    system will be allowed to recover and the market price of electricity.
    Management believes that the system will recover its transition costs.  A
    change in any of the above listed factors or in the current legislation
    could affect the recovery of transition costs and may result in a loss to
    the system.  For additional information relating to industry
    restructuring, see the "Industry Restructuring - Electric" section under
    Management's Discussion and Analysis of Financial Condition and Results of
    Operations.

(3) Commitments and Contingencies

    Capital Expenditures

         Construction Program

         The system is engaged in a continuous construction program presently
    estimated at $248.6 million for the five-year period 1998 through 2002. 
    Of that amount, $60.7 million is estimated for 1998.  The program is
    subject to periodic review and revision.

         Acquisition

         On June 1, 1998, Advanced Energy Systems, Inc. (AES), a wholly-owned
    subsidiary of the System, acquired for $146.3 million all of the issued
    and outstanding shares of capital stock of Harvard University's Medical
    Area Total Energy Plant, Inc. subsidiary (MATEP) and all rights under
    customer contracts owned by Harvard University.  MATEP's principal asset
    is a cogeneration plant that provides heating, chilled water service and
    electricity to several hospitals, medical research centers and teaching
    institutions in the 200-acre Longwood Medical Area of Boston pursuant to
    the contracts that were assigned to AES.  The purchase price was
    established through a sealed bid auction process and the transaction was
    initially financed with a short-term bank loan of $150 million that was
    subsequently reduced with the proceeds from an equity contribution from
    the System to AES of approximately $40 million.  A long-term financing
    agreement for approximately $110 million is expected to be finalized in
    the third quarter of 1998.

         MATEP had revenues of $58 million and net earnings of $7.3 million
    for the fiscal year ended June 30, 1997.  Results for MATEP are included
    in the accompanying Consolidated Condensed Financial Statements from the
    date of acquisition.

         The acquisition was accounted for under the purchase method of
    accounting.  The purchase price was allocated based on the fair value of
    assets acquired and resulted in the recognition of an intangible asset
    amounting to approximately $31 million that is being amortized on a
    straight-line basis over fifteen years.

<PAGE 10>

                          COMMONWEALTH ENERGY SYSTEM

         Based on unaudited data, the following pro forma summary presents the
    consolidated results of operations for the three and six months ended June
    30, 1998 and 1997 as if the acquisition had occurred at the beginning of
    the years presented:

                              Three Months Ended           Six Months Ended
                                    June 30,                   June 30,
                                1998          1997         1998        1997
                             (Dollars in thousands except per share amounts)

Revenues                      $212,581    $235,506       $502,985    $566,841

Net Income (Loss)
  Applicable to
  Common Shares               $   (521)   $ (1,941)      $ 24,335    $ 24,483

Basic and Diluted Earnings
  (Loss) per Common Share        $(.02)      $(.09)         $1.13       $1.14

      The pro forma results do not purport to be indicative of the results of
operations that actually would have resulted had the acquisition been made at
the beginning of the years presented, or of results that may occur in the
future.


<PAGE 11>


                          COMMONWEALTH ENERGY SYSTEM

Item 2.  Management's Discussion and Analysis of Financial Condition
         and Results of Operations

         Financial Condition

         Capital resources of the System and its subsidiaries are derived
    principally from retained earnings.  Supplemental interim funds are
    borrowed on a short-term basis and, when necessary, replaced with new
    equity and/or debt issues through permanent financing secured on an
    individual company basis.  The system purchases 100% of all subsidiary
    common stock issues and provides, to the extent possible, a portion of the
    subsidiaries' short-term financing needs.  These capital resources provide
    the funds required for the subsidiary companies' construction programs,
    current operations, debt service and other capital requirements.

         For the first six months of 1998, cash flows from operating
    activities amounted to approximately $67 million and reflect net income of
    $26.6 million and noncash items including depreciation of $30.6 million
    and amortization of $5.8 million.  The change in working capital since
    December 31, 1998, exclusive of cash and interim financing, amounted to
    $27.6 million and had a positive impact on cash flows from operating
    activities, reflecting a lower level of accounts receivable ($25.3
    million), unbilled revenues ($23.8 million), prepaid taxes ($9.3 million)
    and inventory ($2.9 million) coupled with a higher level of other current
    liabilities ($21.1 million). These factors were offset, in part, by a
    lower level of accrued taxes ($20.1 million), a decline in accounts
    payable ($31.9 million) and a higher level of other current assets ($2.8
    million).

         Construction expenditures for the first half of 1998 were
    approximately $25.1 million, including an allowance for funds used during
    construction (AFUDC) and nuclear fuel.  Construction expenditures and the
    preferred and common dividend requirements of the System ($17.9 million)
    were funded entirely with internally-generated funds.

         The system, through its Advanced Energy Systems, Inc. subsidiary
    (AES), purchased a total energy plant (MATEP), that was formerly owned and
    operated by Harvard University and is located in the Longwood Medical Area
    of Boston, and related contracts for $146.3 million on June 1, 1998.  This
    acquisition was financed, on a short-term basis, through a $150 million
    term loan agreement that will be repaid with the proceeds from a permanent
    financing plan that is expected to be completed during the third quarter. 
    The System, pursuant to the permanent financing plan, has provided a $40
    million equity contribution to AES with a portion of the proceeds from the
    aforementioned term loan agreement.  The permanent financing plan will
    also include a $110 million long-term bank loan to AES.  It is projected
    that this new venture will increase system revenues by approximately $45
    million in 1998 and, on average, by approximately $65 million in the years
    1999 through 2002.

<PAGE 12>

                          COMMONWEALTH ENERGY SYSTEM

         On May 28, 1998, the System announced that three of its subsidiary
    companies (Commonwealth Electric Company, Cambridge Electric Light Company
    and Canal Electric Company) have selected affiliates of Southern Energy
    New England, L.L.C., an affiliate of The Southern Company, to buy
    substantially all of their non-nuclear electric generating assets for $462
    million, an amount that is six times the book value of $79 million.  The
    sale is expected to be completed by year-end 1998 pending receipt of the
    necessary regulatory approvals.  The net proceeds from the sale of these
    assets will be used to mitigate transition costs.

         Results of Operations

         The following is a discussion of certain significant factors which
    have affected operating revenues, expenses and net income during the
    periods included in the accompanying Consolidated Condensed Statements of
    Income.  This discussion should be read in conjunction with the Notes to
    Condensed Financial Statements appearing elsewhere in this report.

<PAGE 13>

                          COMMONWEALTH ENERGY SYSTEM

         A summary of the period to period changes in the principal items
    included in the Consolidated Condensed Statements of Income for the three
    and six months ended June 30, 1998 and 1997 and unit sales for these
    periods are shown below:
                                          Three Months          Six Months
                                         Ended June 30,       Ended June 30,
                                          1998 and 1997        1998 and 1997 
                                                 Increase (Decrease)
                                               (Dollars in thousands)
  Operating Revenues -
      Electric                         $(17,858)   (11.4)%  $(38,858)  (11.6)%
      Gas                                (2,695)    (4.4)    (19,823)  (10.3)
      Steam and other                     2,900     77.1       1,442    13.3
                                        (17,653)    (8.0)    (57,239)  (10.6)
  Operating Expenses -
      Fuel and purchased power          (16,388)   (19.1)    (36,039)  (18.8)
      Cost of gas sold                    4,899     16.0     (11,834)  (11.5)
      Other operation and maintenance   (13,349)   (16.8)    (15,453)  (11.0)
      Depreciation                        1,569     12.3       2,236     7.9
      Taxes -
         Federal and state income         2,192    171.3       1,624    10.5
         Local property and other          (329)    (5.0)       (688)   (4.4)
                                        (21,406)   (10.0)    (60,154)  (12.2)

  Operating Income                        3,753     48.2       2,915     6.7

  Other Income                             (177)   (18.0)       (131)   (8.0)

  Income Before Interest Charges          3,576     40.8       2,784     6.1

  Interest Charges                        1,177     11.6       1,226     6.1

  Net Income                              2,399    179.8       1,558     6.2

  Dividends on preferred shares             (14)    (5.6)        (29)   (5.8)

  Earnings Applicable to Common Shares $  2,413    152.2    $  1,587     6.5

  Unit Sales
    Electric - Megawatthours (MWH)
      Retail                            (34,214)    (3.0)    (27,243)   (1.2)
      Wholesale                          24,885      3.6      (8,122)   (0.4)
                                         (9,329)    (0.5)    (35,365)   (0.8)

    Gas - Billions of British Thermal
          Units (BBTU)
      Firm                               (1,697)   (24.9)     (4,496)  (18.7)
      Interruptible and other               168     14.2         480    19.7
                                         (1,529)   (19.1)     (4,016)  (15.2)

<PAGE 14>

                          COMMONWEALTH ENERGY SYSTEM

         The following is a summary of electric unit sales and gas throughput
   for the periods indicated:
                                   Three Months Ended      Six Months Ended
                                        June 30,               June 30,      
                                     1998      1997         1998      1997 
  Electric Sales - MWH
      Residential                   379,912    420,714     852,131    894,765
      Commercial                    604,001    601,114   1,200,861  1,190,702
      Industrial                    114,247    110,245     215,527    210,017
      Other                           4,955      5,256      11,643     11,921
         Total retail sales       1,103,115  1,137,329   2,280,162  2,307,405
      Wholesale sales               722,048    697,163   1,862,375  1,870,497
         Total                    1,825,163  1,834,492   4,142,537  4,177,902

  Gas Sales - BBTU
      Residential                     2,995      3,775      11,763     13,657
      Commercial                      1,463      1,914       5,515      6,764
      Industrial                        352        697       1,167      2,270
      Other                             297        418       1,120      1,370
         Total firm sales             5,107      6,804      19,565     24,061
      Interruptible                                                          
        and other                     1,354      1,186       2,917      2,437
         Total sales                  6,461      7,990      22,482     26,498
      Transportation                  3,032      2,935       5,399      4,129
         Total throughput             9,943     10,925      27,881     30,627

  Electric Revenues, Fuel and Purchased Power Costs

         Electric operating revenues decreased $17.9 million (11.4%) and
  $38.9 million (11.6%) during the current quarter and first half of 1998,
  respectively, due mainly to lower fuel and purchased power costs ($16.4
  million and $36 million, respectively).

         Fuel and purchased power costs decreased approximately $16.4 million
  (19.1%) and $36 million (18.8%) and reflects a deferral of costs ($15.3
  million and $30.2 million )in conjunction with the system's electric
  restructuring plan as approved by the DTE.  Also contributing to the
  declines in revenue in both current periods were lower fuel costs and a
  decrease in retail unit sales.  As a result of industry restructuring, the
  system's retail electric companies have unbundled rates, provided customers
  with a ten percent rate reduction as of March 1, 1998 and have afforded
  customers the opportunity to purchase generation supply in the competitive
  market consistent with the electric industry restructuring legislation
  further discussed below.  Delivery rates are composed of a customer charge
  (to collect metering and billing costs), a distribution charge, a
  transition charge (to collect stranded costs), a transmission charge, an
  energy conservation charge (to collect costs for demand-side management
  programs) and a renewable energy charge.  Electricity supply services
  provided by the system's retail subsidiaries include optional standard
  offer service and default service.  Amounts collected through these various
  charges will be reconciled to actual expenditures on an on-going basis.

<PAGE 15>

                          COMMONWEALTH ENERGY SYSTEM

  Gas Revenues and Cost of Gas Sold

         Gas operating revenues decreased by $2.7 million and $19.8 million
  during the current quarter and six-month period, respectively, due
  primarily to the considerable declines in firm unit sales.  Also affecting
  revenues in both periods was a lower average cost of gas.

         The decrease in unit sales to firm customers reflects the impact of
  the milder weather conditions experienced during the first half of 1998 on
  all customer segments.  The fluctuation in interruptible and other sales
  reflects the competitive market that exists today in the natural gas
  industry.

  Other Operating Expenses

         For the current quarter and first half of 1998, other operation and
  maintenance decreased $13.3 million (16.8%) and $15.5 million (11%),
  respectively, reflecting the absence of a one-time charge ($17.7 million)
  related to the personnel reduction program (PRP) initiated in the second
  quarter of 1997.  Also contributing to the decrease in the current quarter
  and six-month period were labor savings realized from the aforementioned
  PRP ($1.3 million and $4.4 million, respectively), the absence of storm
  damage costs related to an April 1997 blizzard ($2 million), a reduction in
  the provision for bad debts ($1.5 million in both current periods), and a
  reduction in insurance and employee benefits costs ($1.3 million and $1.6
  million, respectively).  The impact of these factors was offset somewhat by
  higher costs relating to the outsourcing of the information technology,
  telecommunications and network services function ($2.7 million and $6.1
  million, respectively) that includes costs associated with Year 2000
  compliance, and costs associated with new business development ($3.4
  million and $5.6 million, respectively).

         Depreciation increased $1.6 million (12.3%) and $2.2 million (7.9%)
  and reflects the treatment allowed for certain production plant pursuant to
  the electric industry restructuring legislation as well as a higher level
  of depreciable plant.  Federal and state income taxes increased $2.2
  million (171.3%) and $1.6 million (10.5%) and reflect the higher level of
  pretax income.  The decreases of $329,000 (5%) for the quarter and $688,000
  (4.4%) for the six-month period in local property and other taxes was due
  primarily to a decline in payroll taxes attributable to savings realized
  from the aforementioned PRP.

  Other Income and Interest Charges

         During the current quarter and first half of 1998, other income
  declined $177,000 and $131,000 as compared to the same periods in 1997
  primarily due to a lower rate of return from steam production and lower
  equity earnings related to a non-utility investment.

         The increases in total interest charges for the current three and
  six-month periods mainly reflect higher levels of short-term borrowings at
  slightly higher interest rates and the issuance of two new series of long-
  term debt in September 1997 partially offset by maturing long-term debt and
  scheduled sinking fund payments.

<PAGE 16>

                          COMMONWEALTH ENERGY SYSTEM

  Industry Restructuring - Electric

         On November 25, 1997, the Governor of Massachusetts signed into law
  the Electric Industry Restructuring Act (the Act).  This legislation
  provided, among other things, that customers of retail electric utility
  companies who take standard offer service receive a 10 percent rate
  reduction and be allowed to choose their energy supplier, effective March
  1, 1998.  The Act also provides that utilities be allowed full recovery of
  transition costs subject to review and an audit process.  The rate
  reduction mandated by the legislation increases to 15 percent effective
  September 1, 1999 for customers who continue to take standard offer
  service.

         It is likely that a statewide referendum will appear on the ballot
  in November of this year that is seeking to repeal the legislation. 
  Management is unable to predict what the ultimate outcome of this challenge
  will be.

         The system filed a comprehensive electric restructuring plan with
  the DTE in November 1997, that was substantially approved by the DTE in
  February 1998.  The divestiture of the system's non-nuclear generation
  assets and the entitlements associated with its purchased power contracts
  is an integral part of the system's restructuring plan and is consistent
  with the Act.  While the system is encouraged with the treatment afforded
  net non-mitigable transition costs (which, for the system, are primarily
  the result of above-market purchased power contracts with non-utility
  generators) by the legislation and the DTE, the mandated rate reduction has
  had a significant impact on cash flows of the system.  However, the
  successful results of the generation auction, as discussed below, could
  significantly reduce the impact that the rate reductions will have on
  future cash flows.

         In March 1997, the system had submitted a report to the DTE that
  detailed the proposed auction process for selling its electric generation
  assets and the entitlements associated with purchased power contracts.  The
  auction process provided a market-based approach to maximizing stranded
  cost mitigation and minimizing the transition costs that retail customers
  will have to pay for stranded cost recovery.  A request for bids from
  interested parties was issued last August and an Offering Memorandum
  followed in October.  Potential bidders examined all pertinent information
  related to the generating facilities and purchased power contracts in order
  to prepare and submit their first round of bids in mid-December.  Final
  binding bids were submitted on May 8, 1998. 

         On May 27, 1998, the System announced that three of its subsidiary
  companies (Cambridge Electric Light Company, Canal Electric Company and
  Commonwealth Electric Company) had selected affiliates of Southern Energy
  New England, L.L.C., an affiliate of The Southern Company of Atlanta,
  Georgia, to buy substantially all of their non-nuclear electric generating
  assets for approximately $462 million (subject to certain adjustments at
  closing).  These facilities represent 984 megawatts (mw) of electric
  capacity and have an approximate book value of $79 million.

         The plants being sold include: Canal Unit 1 (566 mw) and a one-half

<PAGE 17>

                          COMMONWEALTH ENERGY SYSTEM

  interest in Canal Unit 2 (282.5 mw) located in Sandwich, MA and owned by
  Canal Electric; the Kendall Station facility (67 mw) and the adjacent
  Kendall Jets (46 mw), located in Cambridge, MA and owned by Cambridge
  Electric; five diesel generators (13.8 mw) in Oak Bluffs and West Tisbury
  on the island of Martha's Vineyard that are owned by Commonwealth Electric,
  and a 1.4 percent joint-ownership interest (8.9 mw) in Wyman Unit No. 4
  located in Yarmouth, ME, also owned by Commonwealth Electric.

         The system continues to evaluate bids related to the purchased power
  contracts.  Also, the system is evaluating the disposition of the
  Blackstone Station generating unit (15.3 mw) owned by Cambridge Electric
  and located in Cambridge, MA which is subject to a right of first offer
  held by Harvard University on any divestiture of the facility.

         On July 31, 1998, a formal divestiture filing was submitted to the
  FERC and the DTE that requests approval of the sale of the system's
  generating assets and further proposes (subject to completion of the sale)
  that the current 10 percent rate reduction increase, effective January 1,
  1999, to 12.1 percent for Commonwealth Electric and to 15.2 percent for
  Cambridge Electric.  In addition, the companies propose to increase the
  retail price of standard offer service, starting January 1, 1999, from the
  present rate of 2.8 cents per kilowatthour (kwh) to 3.5 cents.  At the same
  time that the price for standard offer service is increased, the transition
  charge for Commonwealth Electric's customers will decline from 4.08 cents
  per kwh to 3.13 cents and for Cambridge Electric's customers from 2.73
  cents per kwh to 1.56 cents.  These proposed changes are intended to
  further reduce the cost of electricity to customers, to make the market
  increasingly more attractive for independent power suppliers to sell
  electricity directly to consumers, and to reduce the system's cost
  deferrals associated with the pricing of standard offer service.  The
  required approvals of the sale and rate structures are expected to be
  received by year-end 1998.

  Industry Restructuring - Gas

         On July 18, 1997, the DTE directed the ten Massachusetts gas
  utilities, including Commonwealth Gas, to initiate a collaborative process
  that will establish guiding principles and specific procedures for
  unbundling rates and services for all customers.

         The DTE listed six principles that it considers important to the
  success of a competitive natural gas market that will provide safe and
  reliable service at the lowest possible cost to customers.  The natural gas
  market would: (1) provide the broadest possible choice; (2) provide all
  customers with an opportunity to share in the benefits of increased
  competition; (3) ensure full and fair competition in the gas supply market;
  (4) functionally separate supply from local distribution services; (5)
  support and further the goals of environmental regulation; and lastly (6)
  rely on incentive regulation where a fully competitive market cannot or
  presently does not exist.

         In addition, the DTE outlined several specific issues that it
  expects the collaborative to address: (1) services that can be offered on a
  competitive basis; (2) terms and conditions of service; (3) consumer

<PAGE 18>

                          COMMONWEALTH ENERGY SYSTEM

  protections and social programs; (4) mitigation of gas related and non-gas
  related transition costs; (5) third-party supplier qualifications; and (6)
  curtailment principles.  The DTE also suggested that the collaborative
  reconsider the pricing and provision of interruptible transportation
  services.

         On August 18, 1997, the DTE noted that the development of unbundling
  principles and procedures constitutes only a part of the effort necessary
  to develop full customer choice for gas service.  The DTE recognized that
  each local distribution company will be filing a comprehensive unbundling
  proposal at some later date.  In the interim, the DTE directed those
  companies that do not currently have unbundled rates, including Common-
  wealth Gas, to have such rates in effect no later than November 1, 1998.

         Commonwealth Gas and eight other gas utilities initiated the
  Massachusetts Gas Unbundling Collaborative (the Collaborative) on September
  15, 1997, to explore and develop generic principles to achieve the goals
  set forth by the DTE.  Collaborative participants represented a broad array
  of stakeholder interests including the utilities, natural gas marketers,
  interstate pipelines, producers, energy consultants, labor unions, consumer
  advocates and representatives for the DTE, the Massachusetts Attorney
  General's Office, and the Massachusetts Division of Energy Resources.

         On November 15, 1997, the Collaborative filed a status report with
  the DTE that outlined its progress in moving the gas industry to a more
  competitive structure that provides all customers with meaningful access to
  competitive markets consistent with public-policy objectives.  The status
  report summarized the substantive issues that had been the subject of
  Collaborative discussion, including: (1) the disposition of interstate
  pipeline capacity; (2) the unbundling of rates; (3) customer enrollment,
  billing, termination, and information exchange procedures; and, (4)
  consumer protections, low-income discounts, and competitive supplier
  registration.  The status report also established a schedule to implement a
  final unbundling plan by November 1, 1998.

         In accordance with that schedule, the Collaborative submitted to the
  DTE a Rate Unbundling Status Report on January 16, 1998.  The report
  detailed an overall process for developing unbundled rates consistent with
  the DTE's rate structure goals of efficiency, fairness, simplicity,
  continuity and earnings stability.  In response to the Collaborative's
  proposal, the DTE ordered Commonwealth Gas to submit, by April 15, 1998, a
  consensus-based settlement, or partial settlement, of unbundled rate
  tariffs designed according to the general concepts set forth in the report. 
  Subsequently, the DTE granted Commonwealth Gas an extension to reach a
  settlement with the Collaborative's participants.

         On March 18, 1998, the Collaborative filed a second status report
  that summarized the progress made by the Collaborative since it had last    
  updated the DTE on its activities.  The Collaborative reported that it had
  made substantial progress in the areas of rate unbundling and terms and
  conditions for unbundled services.  The report also described at least two
  policy issues, capacity disposition and cost responsibility, on which the
  Collaborative's participants require specific regulatory guidance before
  completing a comprehensive framework for the transition to a more

<PAGE 19>

                          COMMONWEALTH ENERGY SYSTEM

  competitive market structure.

         In response to the March report, the DTE issued a Notice of Inquiry
  to address the Collaborative's unresolved issues.  On May 1, 1998, Common-
  wealth Gas filed initial written comments in the proceeding arguing in
  favor of a mandatory capacity assignment proposal.  On June 8, 1998, the
  DTE, as part of the aforementioned Notice of Inquiry, received final
  comments regarding the feasibility of implementing comprehensive unbundling
  for all local distribution companies by November 1, 1998.  On June 29,
  1998, Commonwealth Gas and three other Massachusetts local distribution
  companies submitted unbundled rate settlements to the DTE for
  consideration.

           The DTE issued a procedural order regarding the Notice of Inquiry
  on July 2, 1998 which stated that the introduction of comprehensive un-
  bundling for all classes of customers for all local distribution companies
  is not feasible by November 1, 1998.  The DTE stated that unbundled rates
  for the four local distribution companies that filed settlements on June
  29, 1998 (including Commonwealth Gas) shall be in place by November 1, 1998
  and that comprehensive unbundling shall be implemented no later than April
  1, 1999.  Also, as part of the July 2, 1998 procedural order, the DTE
  ordered that a set of proposed Model Terms and Conditions be submitted by
  the Collaborative no later than July 15, 1998.  These Model Terms and
  Conditions were submitted on July 10, 1998 and a decision will be issued by
  the DTE no later than September 30, 1998.  The DTE intends to issue an
  order on capacity assignment and cost responsibility by October 30, 1998.

  Environmental Matters

         Commonwealth Gas is participating in the assessment of a number of
  former manufactured gas plant (MGP) sites and alleged MGP waste disposal
  locations to determine if and to what extent such sites have been
  contaminated and whether Commonwealth Gas may be responsible for remedial
  actions.  The DTE has approved recovery of costs associated with MGP sites. 
  Commonwealth Gas is also involved in certain other known or potentially
  contaminated sites where the associated costs may not be recoverable in
  rates.  For further information on other related environmental matters,
  refer to the System's 1997 Annual Report on Form 10-K.

  New Accounting Standards

         In June 1998, the Financial Accounting Standards Board issued
  Statement of Financial Accounting Standards No. 133 (SFAS No. 133),
  "Accounting for Derivative Instruments and Hedging Activities."  SFAS No.
  133 establishes accounting and reporting standards requiring that every
  derivative instrument (including certain derivative instruments embedded in
  other contracts possibly including fixed-price fuel supply and power
  contracts) be recorded on the balance sheet as either an asset or liability
  measured at its fair value.  SFAS No. 133 requires that changes in the
  derivative's fair value be recognized currently in earnings unless specific
  hedge accounting criteria are met.  Special accounting for qualifying
  hedges allows a derivative's gains and losses to offset related results on
  the hedged item in the income statement, and requires that a company must
  formally document, designate and assess the effectiveness of transactions

<PAGE 20>

                          COMMONWEALTH ENERGY SYSTEM

  that receive hedge accounting.

         SFAS No. 133 is effective for fiscal years beginning after June 15,
  1999 and may be implemented as of the beginning of any fiscal quarter after
  issuance but cannot be applied retroactively.  SFAS No. 133 must be applied
  to derivative instruments and certain derivative instruments embedded in
  hybrid contracts that were issued, acquired or substantively modified after
  December 31, 1997 and, at the company's election, before January 1, 1998.

         The system has not yet quantified the impacts of adopting SFAS No.
  133 on its financial statements and has not determined the timing of its
  method of adopting SFAS No. 133.

         In April 1998, the American Institute of Certified Public
  Accountants issued Statement of Position 98-5 "Reporting on the Costs of
  Start-Up Activities" (SOP 98-5).  SOP 98-5 provides guidance on the
  financial reporting of start-up and organization costs and requires that
  these costs be expensed as incurred.  The impact of SOP 98-5 is not
  expected to have a material impact on the system's results of operations or
  financial condition.

  Year 2000

         The system has been involved in Year 2000 compliancy since 1996.  A
  complete inventory and review of software, information processing, delivery
  systems and operational components for certain facilities has been
  completed, and work continues on computer systems wherever necessary. 
  While some computer systems have already been updated, tested and placed in
  production, the system expects to complete the balance of the modifications
  by mid-1999.

         Costs associated with Year 2000 compliancy are being expensed as
  incurred.  The total cost of this project is expected to be funded with
  internally generated funds.

         Management believes that, with appropriate modifications, the system
  will be fully compliant regarding all Year 2000 issues and will continue to
  provide its products and services uninterrupted through the millennium
  change.  Failure to become fully compliant could have a significant impact
  on the system's operations.

  Forward-Looking Statements

         This discussion contains statements which, to the extent it is not a
  recitation of historical fact, constitute "forward-looking statements" and
  is intended to be subject to the safe harbor protection provided by the
  Private Securities Litigation Reform Act of 1995.  A number of important
  factors affecting the System's business and financial results could cause
  actual results to differ materially from those reflected in the forward-
  looking statements or projected amounts.  Those factors include
  developments in the legislative, regulatory and competitive environment,
  certain environmental matters, demands for capital and new business
  development expenditures and the availability of cash from various sources.


<PAGE 21>

                          COMMONWEALTH ENERGY SYSTEM
                          PART II - OTHER INFORMATION

Item 1.     Legal Proceedings

       The System is subject to legal claims and matters arising from its
       course of business including when Cambridge Electric was an intervenor
       in an appeal at the Massachusetts Supreme Judicial Court (SJC) filed
       by the Massachusetts Institute of Technology (MIT) involving a DTE
       decision approving a customer transition charge (CTC) for the recovery
       of stranded investment costs.  By its terms, the CTC was terminated on
       March 1, 1998, coincident with the retail access date established by
       the Massachusetts Legislature in the Electric Industry Restructuring
       Act.  On September 18, 1997, the SJC remanded the CTC matter to the
       DTE for further consideration.  The SJC stated that, although recovery
       of prudent and verifiable stranded costs by utility companies is in
       the public interest and consistent with the Public Utility Regulatory
       Policies Act, the insufficiencies of the DTE's subsidiary findings
       precluded the SJC from undertaking a meaningful review of the DTE's
       calculations that formed the basis of the CTC.  The DTE is in the
       process of determining whether to hear additional evidence in the
       remand or to rely on the record and pleadings already filed.  On
       January 16, 1998 Cambridge Electric submitted to the DTE a customer
       exit charge rate tariff and sought a finding that the tariff would
       apply to MIT.  On July 23, 1998 the DTE issued a ruling which rejected
       the form of customer exit charge rate tariff, but opened a new
       investigation into whether MIT should be required to pay an exit
       charge, and, if so, what the amount of the exit charge should be. 
       Also, the DTE's investigation includes whether this case should be
       joined with the remand proceeding currently before the DTE.  This
       issue is discussed more fully in the System's 1997 Annual Report on
       Form 10-K.  At this time, management is unable to predict the ultimate
       outcome of this proceeding.

Item 2.     Changes in the Rights of the Company's Security Holders

       None

Item 3.     Defaults by the Company on its Senior Securities

       None

Item 4.     Results of Votes of Security Holders

       None

Item 5.     Other Information

       None.


<PAGE 22>

                          COMMONWEALTH ENERGY SYSTEM

Item 6.      Exhibits and Reports on Form 8-K

       (a)   Exhibits

             Exhibit 27 - Financial Data Schedule

             Filed herewith as Exhibit 1 is the Financial Data Schedule for
             the three months ended June 30, 1998.

       (b)   Reports on Form 8-K

             Two reports on Form 8-K were filed during the three months ended
             June 30, 1998.  One report was filed June 5, 1998 for an event
             first reported May 27, 1998 regarding the sale of the system's
             non-nuclear generation assets.  A second report was filed on
             June 12, 1998 relating to the acquisition of a total energy
             plant on June 1, 1998.
<PAGE 23>


                          COMMONWEALTH ENERGY SYSTEM

                                  SIGNATURES

   Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.



                                            COMMONWEALTH ENERGY SYSTEM
                                                  (Registrant)


                                            Principal Financial and
                                               Accounting Officer



                                            JAMES D. RAPPOLI             
                                            James D. Rappoli,
                                            Financial Vice President
                                              and Treasurer




Date:  August 14, 1998