Feasibility of run-of-river hydropower for rural and agricultural productivity in South Africa.

Abstract

The Southern African Community Development (SADC) intends to increase its irrigated area to increase the agricultural productivity of the land. Run-of-river hydropower systems present an attractive solution of providing energy where it is not feasible for alternative energy sources and extend the grid infrastructure to improve the livelihood of rural communities and increase agricultural productivity. The site geographical location and topography of power plants have made it impossible to guarantee fixed costs from suppliers and manufacturers, leading researchers to develop formulae that predict the cost behavioural tendencies of the electro-mechanical components of the power plant as a function of hydropower parameter inputs and other costs. Hydropower systems are very site-specific as they are affected by their geographical location and the site's topography. The difficulties from suppliers and manufacturers in failing to guarantee fixed costs have resulted in designers using developed formulae to determine the scheme's costs. This investigation aimed to develop a model that would allow designers to determine whether run-of-river hydropower would be feasible or not for a specific location in South Africa. This was achieved through a pre-feasibility model based on a '3 Pillar Concept' of social, environmental, and economic test for sustainability, which according to research, has 49 sustainability indicators for run-of-river hydropower systems measured directly or indirectly. The Levelised Cost of Electricity (LCOE) from hydropower was used to determine the economic feasibility of hydropower systems. From previous research, LCOE evaluation for small hydropower projects in developing countries ranged between 0.02USD/kWh and 0.10USD/kWh, making small scale hydropower systems very cost competitive for electricity generation to the grid or schemes for off-grid rural electrification. Run-of-River hydropower systems are classified as small hydropower systems and generate from 1MW to 20MW. The projects demonstrated in this report were Micro and Mini hydropower systems which are significantly larger than Pico hydropower systems. The sites selected for the study are U2H014 located downstream of Albert Falls dam, U3H005 downstream of the Hazelmere dam, U2H052 downstream of Inanda dam, and V1H002 downstream of Woodstock dam. The potential power of the available energy was quantified using available streamflow data. Flow duration curves were developed from streamflow data and were used to develop power duration curves for the hydropower plants. LCOE for the investigated sites ranged between 0.02USD/kWh and 0.10USD/kWh. The power duration curves showed that the smallest power plant was U3H005 and generated 48kW. The groundwater pumping requirements for rural and agricultural productivity is found to be 31.1kW. Results obtained at sites U2H014 and V1H002 were 238kW and 314kW, respectively. The smallest power plant could generate enough power for rural and agricultural productivity with power savings that could be sold to the grid or power the community. The results obtained at the sites were positive and acceptable.