Solar (Photovoltaic) Systems, Energy Use and Business Activities in Maphephethe, KwaZulu, Natal
Literature suggests that energy is both a prerequisite for and essential to development (both social and economic). In order to establish the ability of an alternative energy source —photovoltaic systems - to meet daily requirements, an investigation into current energy usage, expenditure patterns and business applications was conducted. Maphephethe, an area north of Durban in KwaZulu-Natal, was selected for a formal survey, with locally based, trained interviewers interviewing 200 households and businesses. The findings indicated that income levels were slightly above national (rural) norms but displayed a wide variability. Eleven energy sources were used, including candles for illumination, car batteries for television sets, dry batteries for radios and wood for cooking. Paraffin and gas were used for refrigeration. The general attitude towards solar home systems was favourable but the interviewees perceived grid electricity as being better. There did not appear to be any difference between those households that had solar home systems and those that did not. Expenditure saved on traditional energy sources matched that spent on solar syst-ems. Business energy-related potential was present but not developed
Energy, environment and the rural poor in South Africa
The lack of adequate energy services imposes heavy social and environmental costs on poor rural households. The rural energy‐environment interface, however, is prone to oversimplistic analyses, especially in the case of the ‘fuelwood problem’, and to a lack of research. International experience suggests that deforestation is not necessarily an ‘energy problem’ resulting from the cutting of trees for fuelwood ‐ and therefore that it may not have an energy solution, like planting more trees for firewood. Instead, wood scarcity must be understood under multiple use of wood resources, and policies need to be multifaceted if they are to succeed. South African studies show that wood is becoming increasingly scarce in many areas; here fuelwood collection may contribute to deforestation more than suggested by international experience. In addition to the environmental effects of increasing wood scarcity and its social costs, borne largely by women, another serious problem arises from indoor air pollution caused by...
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.