Abstract
Electricity demand in Lesotho has surpassed the main domestic generation of 72-MW hydropower station with 59% capacity deficit currently met by imports from South Africa and Mozambique through costly fixed bilateral contracts. With the abundant renewable energy sources in Lesotho, independent power producers could be incentivized to erect solar PV plants and wind farms to increase local energy security at lower cost and diversify utility's power mix. This article develops a power dispatching approach that prioritizes solar PV and wind generators to aid hydropower station meet demand and only be backed by imports. It uses the Monte Carlo approach to simulate generation adequacy analysis in order to establish monthly average expected demand not supplied (EDNS) and loss of load probability (LOLP) for the baseline case and three dispatch scenarios. According to the analysis, the EDNS for all simulated scenarios never drops to 0 MW, while the LOLP only reaches a minimum of 52% for the scenario with all local renewable energy generators combined. Furthermore, main grid energy imports can be minimized by 22.3% with the introduction of 50-MW solar PV and by 40.2% for 58-MW wind farms. A 59.7% minimization can be obtained by combining solar PV at 50-MW, wind farms at 58-MW and MHP at 72-MW. These introductions would lead to subsequent reductions in power procurement costs of about 6.2% for solar PV alone and 1.11% for both solar PV and wind. However, the inclusion of wind energy alone would lead to slight cost increase of about 0.6%.