Abstract: Apparatus and methods for generating thermal energy from a pulsed DC electric power source utilizing pairs of electrodes disposed in a water medium. Electric pulses are provided at a frequency up to 20 MHz. Efficiencies are obtained when multiple pairs of electrodes are powered by the pulsed DC electric power source. The electrodes may be rods, plates, cylinders, or other useful shapes. The electrodes exposed to water may be a metal or alloy of nickel, platinum, palladium, or tungsten. The DC pulse generator is electrically connected to the electrodes to provide a source of pulsed direct current electric power. The input polarity to the electrodes may be periodically reversed or alternated between the anode and cathode polarity to limit erosion/electroplating of electrode material.