Abstract
Increasing local energy access in developing countries, particularly in off-grid regions where mini-grids are often overloaded, remains a critically underexplored area in energy transition. These regions often face significant technical and economic challenges, such as low generation capacity, high energy costs, limited energy access, and heavy reliance on diesel fuels. This study explores capacity expansion by integrating small-scale geothermal energy into such a mini-grid system to enhance the local energy supply. Unlike commonly studied solar-wind hybrid systems, this study evaluates the largely untapped potential of decentralized small-scale geothermal energy in providing a clean, reliable baseload complement to the variable solar PV system at Eka Awoke, Ikwo, Ebonyi State, Nigeria, at a minimal cost. The linear programming (LP) model presents the first in-depth analysis of the integration of small-scale geothermal energy into an existing mini-grid in sub-Saharan Africa. It evaluates the energy system under four realistic demand scenarios: Baseline, suppressed demand, increased connection demand, and increased connections with eCooking demand scenarios. The results obtained show that the geothermal capacity increased by 21.21% and 77.71% for the increased connection and increased connection with eCooking, respectively, while it decreased by 37.7% for the suppressed demand scenario. These findings provide valuable insights for energy providers and policymakers seeking to decarbonize and design more capacity and cost-effective strategies for increasing local energy access in mini-grids.