TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred System: In the system, the source of electricity is provided by one or more of the following devices, a mechanically driven alternator, an electrically rechargeable storage battery, an alternator or other electrical generator driven by a fluid flow. The generator is powered by the flow within a central heating system. The system further comprises any one or more of the following additional components: a water de-ionizer for de-ionizing water fed to the electrolyzer, a water filter for filtering water fed to the electrolyzer, a pressure gauge on the reservoir for monitoring the pressure in it, a pressure operated cut-out switch to prevent operation of the pump when a pre-defined pressure is obtained in the reservoir, a one way valve located at an outlet of the reservoir to prevent flash-back, a water separator to return water condensed in the reservoir back to the electrolyzer and a control panel to switch between sources of electricity where a set of sources is employed. The gases are supplied as combustion gases to a water heating boiler, where the boiler includes also a supply of carbon based fuel and means for switching between supplies from the gases and the fuel. The excess heat from the electrolyzer can be used for heating. Preferred Electrolyzer: In the electrolyzer, the plastics material is shrunk around the coils. The means for controlling the level of water in the chamber comprises a float valve, where the chamber includes a single outlet for hydrogen and oxygen. Alternatively, the electrolyzer for producing gases from components of an electrolyte comprises a series of similarly shaped side by side conducting plates for acting as electrodes, each separated by a non-conductive gasket, the gasket forming a seal between adjacent plates and forming a cavity between the plates for the electrolyte. The plates each have one or more holes in it, and the electrolyzer further includes one or more ties passing through the holes for compressing the plates to hold them together. The electrolyzer further comprises plastics end plates located at each end of the series of plates, the end plates including an electrolyte inlet and a gas outlet. The conducting plates have a surface roughened by sanding. The electrolyte temperature is controlled to be between approximately 22-28/oC, and preferably about 25 degrees C.