Abstract:
Small scale hydropower used to play a very important role in the provision of energy to urban and rural
areas of South Africa. The national electricity grid however, expanded and offered cheap, coal generated
electricity and a large number of hydropower systems were decommissioned. Unfortunately, large
numbers of households and communities will not be connected to the national electricity grid for the
foreseeable future due to high cost of transmission and distribution systems to remote communities, the
relatively low electricity demand within rural communities and the current expenditure on upgrading
and constructing of new coal fired power stations. Today, small hydropower projects are the most
commonly used option to supply electricity to isolated or rural communities throughout the world
including countries such as Nepal, India, Peru and China.
It was hypothesized that it is technically possible to provide small?scale hydropower (SSHP)
installations for rural electrification in South Africa, and that for specific configurations of penstock
diameter, penstock length and transmission line lengths, SSHP installations are more feasible for rural
electrification than local or national electricity grid extension or even other energy sources such as
diesel generators.
The objective of the study was to identify potential sites for the development of feasible small-scale
hydropower plants within the OR Tambo District Municipality in the Eastern Cape, and the uMzinyathi
District Municipality in Kwa-Zulu Natal, South Africa. The objective was the development of a
feasibility and implementation model to assist in designing and financially evaluating small-scale
hydropower plants for several similarly identified potential small-scale hydropower installations in
South Africa. The implementation model describes steps to be followed in identifying a technically possible and
feasible opportunity to develop a small?scale hydropower site for rural electrification, and categorises
them into three different sections, namely Site Selection, SSHP and Cost Assesment, which combine to
form the implementation model. Continuous referral from the subsequent sections of the study back to
the implementation model provides a comprehensiveness to the model which allows for a sustainable
implementation of the SSHP project from the conceptual phase to the commissioning of the plant.
Several designed small-scale hydropower plants were economically evaluated on Net Present Value,
Internal Rate of Return, Levelised Cost of Energy, Financial Payback Period and Capital Cost
Comparison (CCCR). It was observed that a low levelised cost is not always associated with a low
CCCR and vice versa. The levelised cost of small-scale hydropower is lowered by developing sites with
shorter penstock lengths for higher elevation differences, to obtain a higher head while minimizing
penstock lengths and capital costs. From the financial analysis of several designed installations, generic
formulae for costing a small-scale hydropower plant were developed. By keeping specific variables
constant, design charts for technically executable and financially feasible small-scale hydropower plants
were developed by assuming constant penstock diameters, penstock lengths and potential head
available.
The outcome of this study proved the initial hypothesis. From the feasibility analysis and developed
design charts it was concluded that the levelised cost of small-scale hydropower projects indicate that
the cost of small-scale hydropower for low energy generation is high compared to the levelised cost of
grid connected electricity supply. However, the remoteness of small-scale hydropower for rural
electrification and the cost of infrastructure to connect remote rural communities to the local or national
electricity grid provides a low CCCR and renders technically implementable small-scale hydropower
projects for rural electrification feasible on this basis.