A PSpice Based Analysis in Estimating & Utilizing Excess Energy from Solar Home Systems during Dry Season in Bangladesh

In Bangladesh, Solar Home Systems (SHS's) are usually designed to meet the night loads. The panel generates energy and stores it in the battery during the daytime. To add autonomy to the system, both the panel and battery are oversized so that the load demand can be met for a certain period even if there is no energy production from the solar panel due to the unavailability of sunlight caused by cloudy weather. But, it is seen that during the dry season (February-April), due to the availability of sufficient sunlight and high clearness index, the autonomy rarely needs to be considered. Therefore, the extra energy produced by the panel to meet the autonomy remains unutilized which results in a highly inefficient energy management system. This paper investigates the total excess energy wasted during this period of the year. Using a PSpice model, the total energy waste for a 130 W
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SHS has been simulated. Then considering the total installed capacity of SHS (232 MW) it has been found that almost 49330 MWh of solar energy is annually wasted in Bangladesh which results in a loss of almost 18.5 million USD/year. To compensate this loss, few possible ways of utilizing this energy for economic benefit has also been discussed.