far from possible - it actually takes more energy to pull apart an O-H bond than you get from burning H2. it has to do with the polarity of the bonds (oxygen holds on the hydrogen stronger than another hydrogen atom would). I just looked it up and the heat of combustion of H2 (energy released from burning) is about 280kJ/mol. while the dissociation of H2O (energy to pull it apart) is about 920kJ/mol..... so 3-4 times more energy to pull water apart than released by making it.... now if you strapped a solar panel to the roof and a wind turbine to the front.... maybe...... ...... nah that still wouldnt be enough..... complete bs