NOVELTY - Converting non-fresh water to fresh water involves subjecting non-fresh water to high temperature electrolysis; compressing, cooling and storing separated hydrogen and oxygen gas at elevated pressure; combusting hydrogen and oxygen gas to produce superheated steam at high temperature; collecting superheated steam produced by combustion; recovering heat from superheated steam.    USE - For converting non-fresh water to fresh water, where non-fresh water is selected from seawater, brackish water, waste water, polluted water, and water from source selected from water from oil and gas production, flowback water from fracking, water production from tar sands, water from chemical/industrial/processing plants, water from mining/foundries operations and oil spillage.    ADVANTAGE - The method of converting non-fresh water to fresh water utilizes high temperature electrolysis to decompose the treated non-fresh water into hydrogen and oxygen, thus combustion of hydrogen and oxygen at elevated high pressure prevents air from entering the combustor by preventing the creation of nitrous oxide (NOX). The method provides vast amounts of fresh water are required for oil and gas production, oil and gas fracking and in bituminous sands (tar sands) operations thus significantly reducing the water supply costs and water disposal costs. The process provides fresh water from many non-fresh water sources and does not require the consumption of large amounts of non-renewable fossil fuels, thus significantly contributing to the slowing down of global warming and extending the life of non-renewable fossil fuel reserves.    DETAILED DESCRIPTION - Converting non-fresh water to fresh water involves: (a) subjecting the non-fresh water to high temperature electrolysis where hydrogen and oxygen gas are produced and separated; (b) compressing, cooling and storing the separated hydrogen and oxygen gas at elevated pressure; (c) combusting the hydrogen and oxygen gas at elevated pressure to produce superheated steam at high temperature; (d) collecting superheated steam produced by the combustion in step (c); (e) recovering heat from the superheated steam where at least some of the superheated steam condenses to produce fresh water; and (f) using at least some of the recovered heat as an energy input in step (a). INDEPENDENT CLAIMS are included for following:    (1) a system for producing fresh water comprising a pretreatment unit for pre-treating non-fresh water; a high temperature electrolysis unit for receiving treated non-fresh water and for producing and separating hydrogen and oxygen gas from the treated non-fresh water; a first compressor unit for compressing hydrogen gas produced and separated by the electrolysis unit; a second compressor unit for compressing oxygen gas produced and separated by the electrolysis unit; a hydrogen and oxygen combustor operable at elevated temperature and elevated pressure for producing superheated steam under high pressure temperature and pressure; a collector connected to the combustor for collecting superheated steam produced by the combustor, where the collector is hermetically sealed to the combustor; a storage unit for fresh water produced in the collector;    (2) a high temperature electrolysis unit (T1) comprising a combustor, a collector and a high temperature electrolysis section; and    (3) a high temperature electrolysis unit (T2) comprising of an evaporation chamber section and a high temperature electrolysis section.