<ARTICLE> UT <LEGEND> This schedule contains summary financial information extracted from the balance sheet, statement of income and statement of cash flows contained in Form 10-Q of Commonwealth Energy System for the three months ended June 30, 1999 and is qualified in its entirety by reference to such financial statements. </LEGEND> <CIK> 0000071304 <NAME> COMMONWEALTH ENERGY SYSTEM <MULTIPLIER> 1,000 <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-END> JUN-30-1999 <PERIOD-TYPE> 6-MOS <BOOK-VALUE> PER-BOOK <TOTAL-NET-UTILITY-PLANT> 1,019,352 <OTHER-PROPERTY-AND-INVEST> 14,033 <TOTAL-CURRENT-ASSETS> 320,518 <TOTAL-DEFERRED-CHARGES> 280,398 <OTHER-ASSETS> 176,789 <TOTAL-ASSETS> 1,811,090 <COMMON> 43,081 <CAPITAL-SURPLUS-PAID-IN> 112,309 <RETAINED-EARNINGS> 304,409 <TOTAL-COMMON-STOCKHOLDERS-EQ> 459,799 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <LONG-TERM-DEBT-NET> 384,457 <SHORT-TERM-NOTES> 90,000 <LONG-TERM-NOTES-PAYABLE> 0 <COMMERCIAL-PAPER-OBLIGATIONS> 0 <LONG-TERM-DEBT-CURRENT-PORT> 35,696 <PREFERRED-STOCK-CURRENT> 0 <CAPITAL-LEASE-OBLIGATIONS> 10,576 <LEASES-CURRENT> 1,120 <OTHER-ITEMS-CAPITAL-AND-LIAB> 829,442 <TOT-CAPITALIZATION-AND-LIAB> 1,811,090 <GROSS-OPERATING-REVENUE> 465,234 <INCOME-TAX-EXPENSE> 18,638 <OTHER-OPERATING-EXPENSES> 400,078 <TOTAL-OPERATING-EXPENSES> 418,716 <OPERATING-INCOME-LOSS> 46,518 <OTHER-INCOME-NET> 5,023 <INCOME-BEFORE-INTEREST-EXPEN> 51,541 <TOTAL-INTEREST-EXPENSE> 23,344 <NET-INCOME> 28,197 <PREFERRED-STOCK-DIVIDENDS> 222 <EARNINGS-AVAILABLE-FOR-COMM> 27,975 <COMMON-STOCK-DIVIDENDS> 17,908 <TOTAL-INTEREST-ON-BONDS> 17,008 <CASH-FLOW-OPERATIONS> 55,502 <EPS-BASIC> 1.30 <EPS-DILUTED> 1.30