An integrated modular biomass to electric power generation system is disclosed. The system comprises various subsystem modules including components which may be prefabricated and mounted on separate and portable self-supporting liftable platforms in a factory controlled environment. The modules may include biomass to biofuel conversion and refinement process related modules and power generation modules. The modules may be transported from the factory to a power generation site, which in some non-limiting examples may comprise part of an agricultural or farming site that produces animal and/or agricultural wastes which may be converted to biofuel. The modules are positioned on site and fluidly coupled together to form a complete biofuel powered electric generation system. A plurality of standardized size subsystem modules of several different process or electrical capacities may be provided for selection to form the complete system. The system may include a biogas production process, biodiesel production process, or both.