Centralized PV generation and decentralized battery storage for cost effective electrification of rural areas

A novel technique for the reduction of the overall system cost of PV (photovoltaic) systems in rural areas is presented. This technique consists of centralized PV generation at a maximum power point voltage of between 90 V and 108 V, power distribution at around 85 V, and decentralized battery storage at 12 V (nominal). Maximum power point tracking (MPPT), single axis solar path tracking (daily), and reflectors are used to maximize the energy from the PV array. Decentralized energy storage in every house, with access restricted to the particular house, encourages energy management by the individual households. Load diversity is exploited by charging remaining batteries at a higher rate when some of the batteries are fully charged. Low distribution losses are obtained by charging the 12 V batteries in series, but access to the energy in the 12 V batteries is restricted to the individual households only. Experimental results are presented, including the power conversion efficiencies of the MPPT and the battery regulator, the energy conversion efficiency of a storage battery, and the increase in ampere hours from a PV panel using a three-stage solar path tracker.