<p>The coupler has a geothermal energy generating system and a combined heat and power plant e.g. biogas combined heat and power plant, or a block heat and power plant for bio-oil i.e. rape oil, and/or bio-pellet, where a heat exchanger (1) is provided for heating an exchange medium (a) using waste heat of the combined heat and power plant. An exchange medium outlet line (3) of the heat exchanger is connected with an electrical feed line (5) of the geothermal energy generating system. The electrical feed line is connected with earth. An independent claim is also included for a method for generating electrical energy.</p>
