The supply of electrical energy in Indonesia is predominantly reliant on fossil fuels due to their abundant availability, ease of extraction, and lower cost. However, the continued use of fossil fuels increases CO2 emissions, contributing to the greenhouse effect. Additionally, fossil fuel prices are rising, their reserves are finite, and they require extensive replenishment time. Consequently, a transition from fossil fuels to renewable energy sources is imperative. The Indonesian government has designated Sumba Island as a pilot project under the Sumba Iconic Island (SII) program. Waingapu in East Nusa Tenggara (NTT) is notable for its significant Diesel Power Plant (PLTD) capacity of 9,450 kW, supplemented by a 2,000 kWp Solar Power Plant (PLTS). This study presents a techno-economic analysis of implementing Wind Power Plants (PLTB) and Battery Energy Storage Systems (BESS) to reduce reliance on PLTD operations. The HOMER software is utilized for system optimization, allowing for design, optimization, and evaluation from both technical and economic perspectives. Sensitivity analysis assesses the impact of fuel price increases on the optimal system configuration under current and future conditions, with a total daily energy demand of 115.6 MWh/day. The economic analysis reveals that the existing scenario has a Levelized Cost of Energy (LCOE) of $0.254/kWh. Incorporating wind turbines and BESS reduces the LCOE to $0.136/kWh. Achieving 100% renewable energy penetration with a PV-Wind-BESS configuration generates an LCOE of $0.221/kWh.