Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_68269 ( "Unit" text, "Type" text, "Gross MW" text, "Construction start" text, "Operation start" text )

### Question ###
Operation start of 2015 has what gross mw?

### Accurate SQL ###

SELECT "Gross MW" FROM table_68269 WHERE "Operation start" = '2015'