This paper deals with the performance and techno-economic analysis of micro-hydropower plant consists of array of Helical Savonius hydrokinetic turbines (HSHKT). In this study, an optimal inter-turbine distance (L) and two specific HSHKT array formations, i.e., triangular and staggered are considered on a 69 m river stretch corresponding to a study area of 2.36 km2. River free stream velocity ranges between 0.88 and 1.88 m/s. Sensitivity analyses were carried out in HOMER software based on the free stream velocity and electric load to investigate the feasibility of the standalone hydrokinetic turbine renewable energy systems (RES) suitable for the rural community. Further, optimization analyses were performed considering minimum total net present cost (TNPC) and cost of energy (COE). The optimum RES consists of triangular formation of 24 numbers of HSHKTs, with 524 kWh/d electrical load, 187 numbers of battery and converter of 46 kW, having COE of Rs 8.22/kWh, TNPC of Rs 14.5 × 106 and electric production of 399.5 MWh/yr. TNPC and COE of triangular formation are 4.83% and 9.12% less than staggered formation, whereas electric production of the triangular is 4.99% more than the staggered formation. Thus, based on economic and energy indicators triangular array formation is considered as best for RES configuration.