Off-grid photovoltaic system losses

Although some progress has been made in recent years, ensuring universal access to electricity remains a major challenge in many countries in sub-Saharan Africa, particularly in rural areas. In light of this challenge, solar photovoltaic (PV) mini-grid systems have emerged as a promising solution for off-grid electrification.

The unavoidable system losses were quantified as inverter losses, maximum power point tracking losses, battery losses, and polarization losses. The study also provides insights into potential approaches to combat these losses and can become a useful guide to better visualize the overall phenomenology of a PV System.

However, it is also important to note that a low PR value for an off-grid PV plant does not necessarily mean that the system is experiencing technical difficulties. Instead, it can be caused by a poor match between the MG system's installed capacity and electricity demand.

The average on-site PV module and overall system efficiencies are 9.85% and 8.76%. The average daily capture losses and system losses are 2.75 kWh/kWp and 0.40 kWh/kWp. The mini-grid operates at a temperature-corrected performance ratio (PR corr) of 42%. The power supply from the PV mini-grid could not satisfy the daily load/demand.

Furthermore, the detailed PV array losses were classified as mismatch power losses, dust accumulation losses, temperature effects, material quality losses, and ohmic wiring losses. The unavoidable system losses were quantified as inverter losses, maximum power point tracking losses, battery losses, and polarization losses.

In this regard, successful experiences of rural electrification using off-grid PV mini-grid systems have been documented, for example, in India, Kenya, Tanzania, Nepal, and Namibia (Come-Zebra et al., 2021), (Pedersen et al., 2021).