CREATE TABLE table_name_48 (commercial_operation VARCHAR(255), gross_capacity VARCHAR(255), electricity_grid VARCHAR(255))
Which Commercial Operation has both a Gross Capacity of 417 mw and an Electricity Grid 27.12.1971?
    
SQL: SELECT commercial_operation FROM table_name_48 WHERE gross_capacity = "417 mw" AND electricity_grid = "27.12.1971"