Pressure retarded osmosis (PRO) process is an interesting membrane technology for alternative power generation operating based on difference in osmosis pressure between river water and seawater. Water from river having a low salinity permeates through a membrane to the other side where elevated pressure seawater having higher salinity flows. The permeated water is then passed through a turbine to generate power. To date, there are a few works on development of mathematical models for predicting water flux, power density, and efficiency under specific conditions. The objective of this work is to investigate the effects of parameters to find the best operating conditions such as feed flow rate, water resources and membrane to obtain the highest performance in term of power density. The process simulation of PRO is performed by using Aspen Custom Modeler and Aspen Plus software. Thermodynamic analysis was studied for evaluation efficiency of system to compare with theoretical power generation. Moreover, the PRO process is scaled up to pilot scale for practical application. The capital cost is evaluated to find the possibility in power plant construction. The results show maximum net power of 15.99 kW and thermodynamic efficiency of 18.20% under river water as feed solution and using Lab TFC-PRO-1membrane.In addition, using Lab TFC-PRO-1 membrane reports minimum unit capital cost about $11,500 kW-1. Finally, the low quality resources that is waste water and brackish water which was used to benefit for power production by environmental friendly system.