Clean and sustainable energy holds preeminent importance from a socio-environmental standpoint and can be achieved through the implementation of a Hybrid Renewable Energy System (HRES). As well as ensuring the stable and reliable operation of power systems amidst the increasing integration of renewable energy sources, precise source forecasting becomes indispensable. Thus, this paper presents a pioneering HRES design incorporating Photovoltaic (PV), Wind Turbine (WT), and Biogas Generator (Bio) technologies, wherein animal manure is utilized as biomass for the sustainable valorization of animal waste. The preliminary objective of this study is to address the prevailing gaps to attain sustainable energy production that is both cost-optimal and technically efficient. Consequently, this paper investigates source forecasting through time series modeling, and assesses the techno-environmental and economic viability of HRES (both off-grid and on-grid) within the northeastern state of India, specifically focusing on the case study of the Cachar district in Assam state. Moreover, real data analysis is conducted to model and optimize the hybrid system. The findings reveal promising outcomes in terms of cost, emissions, and electrical energy potential, which are presented and comprehensively discussed. Furthermore, a sensitivity analysis is performed to assess the system's robustness. The analyzed results are compared and validated with existing literature including different energy economics with optimum configurations. Finally, this study endeavors to project a future power system for one of the prominent regions in Assam, an Indian state.