A wind energy converter 10 comprises a horizontal axis wind turbine 12 including a plurality of blade members 14 rotatable about a generally horizontal axis. A mass member 16 is movable along the or each blade member 14 under the action of radial forces induced by rotation of the blade members 14 and under the action of gravitational force, and movement of the or each mass member 16 is arranged to provide for conversion of the wind energy. Also described is a power generating system 200, 240 including a heat recovery arrangement 216, comprising a heat exchanger arrangement 218 and an expander 222.