The present disclosure is directed to a waste heat recovery system used in conjunction with a power source system. A pump may pressurize a working fluid to a set pressure threshold and feed the working fluid through a fluid flow path. An evaporator and a condenser may each connect to the fluid flow path. Connected to each the evaporator and the condenser may be a turbine able to receive the working fluid when the working fluid is above the set pressure threshold and a predetermined thermal threshold. An electric machine having a motor mode or a generator mode may then attach to the turbine. Attached to the other end of the turbine may be a shaft coupling also attached to the pump. The pump may be powered by the electric machine operating in a motor mode through the shaft coupling to provide pressure to the waste heat recovery system.