Abstract: A heating system comprising: a liquid supply system; a cell configured to: receive liquid from the liquid supply system, provide heating thereof, and output heated fluid; a work extraction system configured to extract useable work from heated fluid output from the cell; wherein the cell comprises: (i) a housing arranged to define an internal portion for receiving liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to fluid in the internal portion; and wherein the electrodes are configured to apply electrical energy to said fluid in the internal portion to generate one or more bubbles of plasma for releasing energy into said fluid in the internal portion and the housing to provide heating of the fluid in the internal portion.