17 September 2012 - According to Consultancy Africa, medium, small (less than 10MW), and micro (less than 100kW) hydro are now viewed by many as more viable alternatives to large scale projects for a number of reasons. Small hydro schemes are among the most environmentally friendly available as they are normally run-of-the-river designs and do not alter river flow dramatically.
Perhaps the greatest advantage of small hydro is its capacity to electrify isolated communities, giving small local businesses the tools to upscale and, of course, dramatically improving the inhabitants’ quality of life. Furthermore, large hydroplants are often environmentally unsustainable, have high transmission costs, are located far from grids, and have high initial capital and start-up costs. Small and micro hydro have low capital requirements. For example a 6.0 kW system (large enough to drive an electric mill and provide light for a community of 500) would cost approximately US$7,800. Thus, the private sector may compete in supplying electricity to rural populations and developing projects.
Indeed, most of the World Bank funding for hydro projects goes to small hydro. Moreover, few rivers can suitably supply large facilities. On the other hand, East Africa has many smaller rivers, which do not suffer in times of drought and can continuously supply power.
A fine example of micro hydro’s success in rural communities is the Tungu-Kabri micro-hydro power project. A joint development by the non-governmental organisation (NGO), Practical Action East Africa, and the Kenyan Ministry of Energy, and funded by the United Nations Development Programme (UNDP), the 18 kW project benefits 200 households in the Mbuiru village river community. The facility alleviates the environmental problems associated with using wood (deforestation) and dung for cooking, diesel for milling and kerosene for lighting. Following assessment of the site and river flow records, the project was constructed by villagers who laboured together every Thursday for two years until the project finally came to fruition and was operational.
East African governments are increasingly taking notice of small and micro hydro. Uganda and Rwanda have programmes in place specifically to encourage private sector sponsorship of such projects, with Uganda injecting an extra 30MW into the grid through this method. Kenya’s state energy company, KenGen, operates seven mini-hydro stations in various parts of the country, built by Europeans before independence (1920s − 1950s). However, the potential of small hydro has yet to be fully recognised.
Overall, considering falling precipitation levels and changing weather patterns, a shift to micro and small hydro is advisable. Mini hydro has a particular advantage in that it is suitable for private sector investment and can be used in decentralised areas. Small hydro would also save governments money by not paying for expensive emergency power when large plants fail due to drought. In terms of profit margins and large business practices, large hydro does provide a more economical incentive per US$/kW but from an energy security perspective and with a view to rural electrification, small hydro is a preferable and more sustainable way forward.