<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 nine months ended September 30, 1998 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-31-1998 <PERIOD-END> SEP-30-1998 <PERIOD-TYPE> 9-MOS <BOOK-VALUE> PER-BOOK <TOTAL-NET-UTILITY-PLANT> 1,089,617 <OTHER-PROPERTY-AND-INVEST> 13,135 <TOTAL-CURRENT-ASSETS> 172,793 <TOTAL-DEFERRED-CHARGES> 262,921 <OTHER-ASSETS> 0 <TOTAL-ASSETS> 1,538,466 <COMMON> 43,068 <CAPITAL-SURPLUS-PAID-IN> 112,075 <RETAINED-EARNINGS> 291,585 <TOTAL-COMMON-STOCKHOLDERS-EQ> 446,728 <PREFERRED-MANDATORY> 11,380 <PREFERRED> 0 <LONG-TERM-DEBT-NET> 475,317 <SHORT-TERM-NOTES> 74,050 <LONG-TERM-NOTES-PAYABLE> 0 <COMMERCIAL-PAPER-OBLIGATIONS> 0 <LONG-TERM-DEBT-CURRENT-PORT> 56,653 <PREFERRED-STOCK-CURRENT> 820 <CAPITAL-LEASE-OBLIGATIONS> 11,251 <LEASES-CURRENT> 1,375 <OTHER-ITEMS-CAPITAL-AND-LIAB> 460,892 <TOT-CAPITALIZATION-AND-LIAB> 1,538,466 <GROSS-OPERATING-REVENUE> 714,501 <INCOME-TAX-EXPENSE> 20,449 <OTHER-OPERATING-EXPENSES> 631,493 <TOTAL-OPERATING-EXPENSES> 651,942 <OPERATING-INCOME-LOSS> 62,559 <OTHER-INCOME-NET> 14,393 <INCOME-BEFORE-INTEREST-EXPEN> 76,952 <TOTAL-INTEREST-EXPENSE> 34,258 <NET-INCOME> 42,694 <PREFERRED-STOCK-DIVIDENDS> 708 <EARNINGS-AVAILABLE-FOR-COMM> 41,986 <COMMON-STOCK-DIVIDENDS> 26,196 <TOTAL-INTEREST-ON-BONDS> 26,708 <CASH-FLOW-OPERATIONS> 69,257 <EPS-PRIMARY> 1.95 <EPS-DILUTED> 1.95