A system for conversion of heat energy into electricity, the system comprising: an electric generator having a power output of 5MW or less, said generator having a proximal end, a distal end, a generator rotor and a stator, said generator rotor being disposed for rotational movement within said stator about a rotational axis, said generator also including a first magnetic radial bearing positioned adjacent said proximal end, and a second magnetic radial bearing positioned adjacent said distal end, said first and second magnetic radial bearings (88a, 88b) surrounding said generator rotor and retaining said generator rotor, during operation, in substantially coaxial alignment with respect to said rotational axis; and an overhung turbine having a housing with a cavity, at least one stator and at least one turbine rotor supported for rotational movement relative to said at least one stator about said rotational axis and positioned in said cavity, said at least one turbine rotor being coupled with said generator rotor so as to rotationally drive said generator rotor, said turbine having a first end attached to said proximal end of said generator, said turbine including an inlet for receiving working fluid at a first temperature and an outlet for exhausting said working fluid at a second temperature lower than said first temperature, said outlet being positioned proximate said first end of said turbine so as to minimise heat transfer to said generator, characterised in that said at least one stator includes a plurality of stator plates, said at least one turbine rotor includes a plurality of turbine rotor plates, said stator plates being positioned in alternating, interdigitated relationship with the turbine rotor plates and said stator plates and turbine rotor plates have substantially flat and substantially parallel contact surfaces (130, 132, 134, 136), wherein said plurality of stator plates and said plurality of rotor plates together form a cartridge that is sized and configured to be releasably mounted as a unitary assembly in said cavity in said housing; said turbine further including a plurality of stator spacer segments that are sized to provide a gap between a radially outermost portion of the rotor plate and a radially innermost portion of the spacer segment. an electric generator having a power output of 5MW or less, said generator having a proximal end, a distal end, a generator rotor and a stator, said generator rotor being disposed for rotational movement within said stator about a rotational axis, said generator also including a first magnetic radial bearing positioned adjacent said proximal end, and a second magnetic radial bearing positioned adjacent said distal end, said first and second magnetic radial bearings (88a, 88b) surrounding said generator rotor and retaining said generator rotor, during operation, in substantially coaxial alignment with respect to said rotational axis; and an overhung turbine having a housing with a cavity, at least one stator and at least one turbine rotor supported for rotational movement relative to said at least one stator about said rotational axis and positioned in said cavity, said at least one turbine rotor being coupled with said generator rotor so as to rotationally drive said generator rotor, said turbine having a first end attached to said proximal end of said generator, said turbine including an inlet for receiving working fluid at a first temperature and an outlet for exhausting said working fluid at a second temperature lower than said first temperature, said outlet being positioned proximate said first end of said turbine so as to minimise heat transfer to said generator, characterised in that said at least one stator includes a plurality of stator plates, said at least one turbine rotor includes a plurality of turbine rotor plates, said stator plates being positioned in alternating, interdigitated relationship with the turbine rotor plates and said stator plates and turbine rotor plates have substantially flat and substantially parallel contact surfaces (130, 132, 134, 136), wherein said plurality of stator plates and said plurality of rotor plates together form a cartridge that is sized and configured to be releasably mounted as a unitary assembly in said cavity in said housing; said turbine further including a plurality of stator spacer segments that are sized to provide a gap between a radially outermost portion of the rotor plate and a radially innermost portion of the spacer segment.