This paper concerns on modeling of stand alone biomass and solar energy system in Sarawak. Sarawak state needs to develop a number of small power generations in remote areas using stand alone system. Stand alone power systems are of special interest combined with renewable energy design in areas not connected to the capital electric grid. The ultimate goal of this project is to obtain a reliable autonomous system with the optimization of the components size and the improvement of capital cost. Simulated model for photovoltaic system is designed using MATLAB Simulink together with PSIM and model for biomass is designed using HoneyWell software to investigate the design and the performance of stand-alone renewable energy systems. Furthermore, the Hybrid Optimization Model for Electric Renewable (HOMER) software is important to develop the cost optimization analysis. The costs for both renewable systems are optimized, compared and analyzed. For a particular scenario, inputs to HOMER include load data, renewable resource data, system component specifications and costs, and a variety of information of optimization, such as number of components in order to obtain the best possible system for rural areas.