Technical-economic optimisation of a 666 kWp PV plant under semi-arid constraints: Design parameters, wiring losses and cleaning strategy

Photovoltaic (PV) plants in semi-arid, dust-intensive environments require simultaneous optimisation of geometric design, electrical infrastructure, and maintenance strategy to minimise the levelized cost of energy (LCOE). This study presents an integrated techno-economic framework applied to a real 666 kWp PV plant located in a quarry in Meknes, Morocco. The approach combines PV*SOL hourly simulations, Excel-based economic modelling, and a 25-year multi-scenario analysis integrating a soiling rate of 0.1%/day across 6 cleaning technologies and 8 cleaning frequencies. An analytical equation was developed to help calculate energy losses as a function of solar panels' orientation and inclination. Another relationship allows a quick estimation of the energy losses due to shading induced by adjacent panel rows as a function of the row spacing factor. It was found that the use of aluminium conductors significantly reduces by nearly 60% this component of the capital expenditure (CAPEX) while maintaining voltage drop below 3%. We also determined that weekly cleaning using a remote-controlled tractor-mounted brush is the best among the investigated 48 cleaning strategies. The integrated approach reduces the LCOE by 25.8% relative to the current design. It is expected that the same improvement could be observed in similar solar plants. Measured data during 2024 showed that PV*SOL simulation overestimated the energy production by 11.2%.