Although electric energy is cheap and plentiful in developed countries, it is still very much a luxury in much of the rest of the world. In order to illuminate their homes and communities after dark, most families are forced to rely on candles or kerosene, neither of which is very safe, economical, or provides a steady, clean source of light. In recent years, there has been significant progress made to utilise sunlight, one of the most abundant and economical sources of energy available and the study and development of photovoltaic technologies which have enabled the conversion of this solar energy into a reliable, storable electric light.
In Karagwe District, Tanzania, a non-governmental organization called the Karagwe Development Association (KARADEA) brought this technology to East Africa through the KARADEA Solar Training Facility (KSTF). It was through this organization that solar-powered lanterns were introduced to the general population here. Unfortunately, although the lanterns had an anticipated lifespan of several years, most were returned to the facility within six months with the explanation that they no longer worked.
It is the goal of this paper to determine the cause for the severely reduced lifespan of these lanterns, and to propose how this technology might better serve the populations who most need it most.
To ensure a complete understanding of the technology, a thorough explanation is undertaken of each of the main components of the photovoltaic system: the photovoltaic generator (i.e. the solar cell), the battery, the charge controller and the load (in this particular examination, the lantern).
Ideally, the research would have been carried out on location in Tanzania, but due to financial constraints, this was not possible. Two of the incapacitated lanterns that had been returned to the KSTF were sent to be studied in the laboratory at SERC, and correspondence between the author and various members of this NGO provided the basis for the research conducted and subsequently reported in this paper.
The lanterns sent for study from Tanzania underwent detailed examination and testing regimens, which, when combined with the details provided by the first-hand users at the KSTF, provided several suggestions as to the possible problem that had initially caused the breakdown of these devices. These possibilities are then examined in greater detail and held up alongside the results of several laboratory experiments to arrive at what appears to be the primary cause of the breakdown of the...
