Systems and methods for generating electrical power in an organic Rankine cycle (ORC) operation include one or more heat exchangers incorporated into mobile heat generation units, and which will receive a heated fluid flow from one or more heat sources, and transfer heat therefrom to a working fluid that is circulated through an ORC unit for generation of power. In embodiments, the mobile heat generation units comprise pre-packaged modules with one or more heat exchangers connected to a pump of a recirculation system, including an array of piping, such that each mobile heat generation unit can be transported to the site and installed as a substantially stand-alone module or heat generation assembly.