Energy payback time analysis and return on investment of off-grid photovoltaic systems in rural areas of Tanzania

Abstract

Owing to a vast land area, abundant solar radiation, and overseas support, the use of photovoltaics (PV) as a source of electricity is rapidly spreading in Sub-Saharan Africa. To understand the actual application situations, two cases of PV electricity generation systems in the rural areas of Tanzania were investigated via life cycle assessment. The energy payback time (EPBT) calculated from the utilisation of the PV systems, taking into consideration the inventory data of the International Energy Agency, revealed an unsatisfactory performance. Specifically, the EPBTs based on actual power generation at the sites greatly exceeded the expected value-based solar radiation calculations. At one site, the EPBT even exceeded the lifespan of the PV panel, indicating that energy recovery was impossible. With respect to the energy return on investment (EROI), it was evident that the income generated from the investments was insufficient to cover current operational costs, suggesting negative returns on investment. Conversely, diesel power generation appeared to be more suitable in these areas owing to the low and discontinuous demand for power. Furthermore, the operation of a more efficient PV system would require improved maintenance and management, as well as an increase in the demand for electricity.