To provide a hybrid water treatment for a high temperature steam generator advantageous in cost and time consumption.

A steam generation system includes: an oxygenated water treatment (OWT) sub-system configured to generate water having oxidizing chemistry; a steam generation sub-system configured to convert the water having oxidizing chemistry into steam having oxidizing chemistry; a temperature reducer or other injection device or devices configured to add an oxygen scavenger to the steam having oxidizing chemistry to generate steam having less oxidizing or reducing chemistry; and a condenser configured to condense the steam having less oxidizing or reducing chemistry into condensed water.