<ARTICLE>  UT
<MULTIPLIER> 1,000
                                
<PERIOD-TYPE>                      9-MOS
<FISCAL-YEAR-END>                      Dec-31-1997
<PERIOD-END>                           Sep-30-1998
<BOOK-VALUE>                             PER-BOOK
<TOTAL-NET-UTILITY-PLANT>               2,308,405
<OTHER-PROPERTY-AND-INVEST>               331,623
<TOTAL-CURRENT-ASSETS>                    248,444
<TOTAL-DEFERRED-CHARGES>                  180,934
<OTHER-ASSETS>                                  0
<TOTAL-ASSETS>                          3,069,406
<COMMON>                                  449,697
<CAPITAL-SURPLUS-PAID-IN>                  (1,674)
<RETAINED-EARNINGS>                       461,430
<TOTAL-COMMON-STOCKHOLDERS-EQ>            910,150
<PREFERRED-MANDATORY>                          62
<PREFERRED>                                89,000
<LONG-TERM-DEBT-NET>                      859,575
<SHORT-TERM-NOTES>                          6,741
<LONG-TERM-NOTES-PAYABLE>                       0
<COMMERCIAL-PAPER-OBLIGATIONS>                  0
<LONG-TERM-DEBT-CURRENT-PORT>              36,287
<PREFERRED-STOCK-CURRENT>                       0
<CAPITAL-LEASE-OBLIGATIONS>                     0
<LEASES-CURRENT>                                0
<OTHER-ITEMS-CAPITAL-AND-LIAB>          1,168,288
<TOT-CAPITALIZATION-AND-LIAB>           3,069,406
<GROSS-OPERATING-REVENUE>                 748,599
<INCOME-TAX-EXPENSE>                       70,854
<OTHER-OPERATING-EXPENSES>                519,476
<TOTAL-OPERATING-EXPENSES>                590,330
<OPERATING-INCOME-LOSS>                   158,269
<OTHER-INCOME-NET>                          7,908
<INCOME-BEFORE-INTEREST-EXPEN>            166,177
<TOTAL-INTEREST-EXPENSE>                   54,370
<NET-INCOME>                              111,807
<PREFERRED-STOCK-DIVIDENDS>                 2,930
<EARNINGS-AVAILABLE-FOR-COMM>             108,877
<COMMON-STOCK-DIVIDENDS>                   75,807
<TOTAL-INTEREST-ON-BONDS>                  43,426
<CASH-FLOW-OPERATIONS>                    261,447
<EPS-PRIMARY>                                1.76
<EPS-DILUTED>                                1.76