Development of a patented 10KWe free piston gas expander (FPGE) for low-cost off-grid power generation from locally available heat sources. The FPGE is an Organic Rankine Cycle sub-system that can be integrated into a wide range of distributed power generation applications including biogas/biomass to power, exhaust waste heat to power (new and retrofit) and concentrated solar power systems. The objective of this mid-stage project is to demonstrate a modular 10KWe FPGE prototype and verify efficiency & performance through lab testing. The close integration of multiple components within the gas expander module improves system efficiency, packaging and cost. The 25 month project involves: System design & simulation; Component development; System integration; Lab testing & model validation. Final output will include the design & testing of an opposed free piston gas expander sub-system whose many applications will assist in meeting all aspects of the energy trilemma and are of direct relevance to the energy access needs of developing countries.