Abstract: Process for harnessing the energy of the natural movements of a heaving liquid mass including the following steps: providing a vessel floating on said liquid mass, the vessel having a compartment containing an auxiliary liquid; allowing the vessel to follow the natural movements of the heaving liquid mass thereby causing reciprocating motion of said auxiliary liquid; and translating the energy developed by the reciprocating motion of said auxiliary liquid into electrical energy. Apparatus for implementing the said process including a vessel suitable for floating on a heaving liquid mass, and having at least one compartment for receiving an auxiliary liquid; and means for translating into electrical energy the energy developed by reciprocating motion of said auxiliary liquid caused by the vessel following the natural movements of the heaving liquid mass.