Energy is the one of the critical tools that ensure the development of the countries. Since almost no country is completely energy independent, it is very important for countries to use the available energy efficiently and to produce their own energy from renewable energy sources. Multi-generation systems combine various cycles and processes to produce number of outputs and valuable market products using one or multiple energy sources as input. By creating a multi-generation system powered by renewable sources can increase system efficiency and provide some additional outputs such as hydrogen, heating, cooling, and domestic hot water. In this thesis, a novel multi-generation system consisting of a biomass gasification cycle, a double-flash geothermal cycle, an Organic Rankine Cycle and a PEM electrolyzer subsystems, is proposed to increase the efficiency and energy production from biomass and geothermal energy sources instead of using a single source for a single output. The proposed system is analyzed in terms of energy, exergy, and environmental impact point of view. By performing parametric studies for biomass flow rate, turbine inlet temperature, and single-objective optimization, effects on thermodynamic behavior and environmental impact are investigated for subsystems and overall system. The best operating conditions are determined. The findings indicate that energy efficiency of the proposed multi-generation system is 75% higher than a double-flash geothermal power plant. Based on the parametric study, biomass mass flow rate is encountered as the most significant parameter, which caused an 11.7% increase in energy efficiency, and 225% increase in environmental impact cost.