Least-Cost Pathway to Reduce The Gambia's Dependence on Imported Energy While Improving Power System Reliability: A Capacity Expansion Model

Abstract

The Gambia’s electricity sector remains heavily dependent on imported energy, exposing the country to price volatility, foreign exchange pressures, and persistent supply insecurity. This thesis investigates the least-cost pathway to reduce this dependence using a capacity expansion model applied across three planning horizons, 2025, 2030, and 2035, drawing on a real demand profile constructed from 329 daily operation reports from The Gambia’s National Water and Electricity Company (NAWEC) covering the 2025 calendar year. Modelling results show that full energy independence requires between 584 MW and 1,156 MW of solar PV and between 130 MW and 222 MW of battery storage, at an additional annualised cost ranging from $7.09 million per year at current demand to $15.14 million per year by 2035. The least-cost pathway is unambiguously a clean energy pathway, new diesel generation was found to be economically uncompetitive across all scenarios. Sensitivity analysis identifies an import tariff crossover of approximately $131/MWh, above which full energy independence becomes economically optimal without policy support. The thesis also examines the institutional, financial, and technical barriers to implementation, and provides evidence-based recommendations to support a realistic and affordable energy transition for national planners and policymakers.