A portable electrolyzer includes an electrolyze chamber with an anode and a cathode as electrodes, a membrane, a water source, such as a water storage vessel, a gas tank, a gas compressor, an electric power supply, and a pulse-width modulator. The electrolyzer further includes i) a thermoelectric cooler attached to the electrolyze chamber and/or a gas tank, ii) an ultrasonic generator connected to at least one electrode and/or at least one sonotrode, and/or iii) a mixer capable of mixing the aqueous phase inside the electrolyze chamber. A process to generate and store hydrogen with the electrolyzer, the use of the electrolyzer e.g. for welding with a hydrogen flame, to convert electricity from renewable energies into hydrogen and to store said electricity in the form of hydrogen, and/or for heat generation by burning hydrogen in a porous burner are also disclosed. Furthermore, a blowtorch including the electrolyzer is disclosed.