Long term assessment of standalone PV systems for rural communities

The application of the standalone PV power system is currently experiencing significant increase and it is expanding vastly as an alternative source of electricity for remote areas. In the Palestinian territories, most of the electricity is provided by the neighbouring countries which imposes a burden on the Palestinian economy due to the instability of the electricity supply and fluctuation in its tariff, especially in the remote villages. To mitigate this problem, the Palestinian energy authority and the energy research centre at An-Najah National University worked on electrification of many small communities and villages by using centralized and decentralized solar PV systems. The aim of establishing these pilot systems is to investigate their viability in meeting the variable load demand of rural communities. In this paper, long term performance assessment of two 4.8 kW standalone PV pilot systems at two different villages are depicted using measured data such as: solar irradiation, energy yield and load demand. The analysis of this data shows that PV system output during the 4-5 years of operation is very sensitive to the site load. The unused energy of the storage battery is the key factor of having a low performance ratio which is found in the range of 0.25- 0.65. The PV system output at local irradiation conditions are simulated using PVSYST software, and high consistency with the measured output is observed. System yield is simulated at different PV array tilt angles and orientations to optimise the PV array area. The simulation results illustrate that adopting the two axis solar tracking mode for standalone PV systems has significant impact on its output. It can reduce the size of the fixed PV array of the selected rural communities by up to 50% of the existing size. It is proposed to connect groups of villages with a local micro grid which can be fed by the surplus energy from the different standalone systems.