Optimal resource integration in a decentralized renewable energy system: Assessment of the existing system and simulation for its expansion

• Optimality of the existing off-grid PV system is assessed by using HOMER software.
• Integration of additional renewable resources to the existing system is simulated.
• The original DPR is reviewed and improvements for future works are recommended.
• The system expansion process is optimized by HOMER vis-à-vis load growth scenarios.
• Effectiveness of the “phased approach” is discussed in terms of financial viability.

Micro-grids are actively employed for rural electrification along with integrated renewable energy systems in developing countries. For determining their optimal configurations, it is often challenging in obtaining accurate input data, particularly prospective electricity loads and local renewable resource availability. In this study, the configuration of the off-grid 120 kWp PV system in West Bengal, India is reassessed by using the optimization software, HOMER. With an assumption that excess biomass resources would be available as a result of successful introduction of fuel-saving devices such as solar cookers, a PV–biomass–battery system, which consists of 30 kW PV array and 20 kW biomass gasification-based power plant (BGPP), turns out to be the most economically feasible option. Compared with the actual system, the net present cost (NPC) and cost of electricity (COE) are significantly lowered. Furthermore, in order to verify effectiveness of “phased approach” for developing the off-grid renewable energy system, which has been proposed in the authors' previous study, the system expansion process is simulated by HOMER according to three different load growth scenarios. It is found from the simulation that adjustment of the system size becomes possible with more accurate load estimation at the time of expansion, which may lead to lower operation and maintenance (O&M) costs and COE. As a result of the increased level of tariff revenue from additional consumers, the expansion process would provide an opportunity for enhancing community welfare and financial viability of the project.