Water for people.pdf - WHO Thailand Digital Repository

2 6 0 / C H A L L E N G E S T O L I F E A N D W E L L - B E I N GDeveloping Energy to Meet Development NeedsBox 10.4: Advantages and disadvantages of small-scale hydropower projectsMicro-hydro systems are mostly ‘run-of-the-river’ systems,which allow the river flow to continue. This is preferablefrom an environmental point of view as seasonal river flowpatterns downstream are not affected and there is noflooding of valleys upstream of the system. A furtherimplication is that the power output of the system is notdetermined by controlling the flow of the river, but insteadthe turbine operates when there is water flow and theenergy output is governed by the actual flow. Therefore, acomplex mechanical governor system is not needed, whichreduces costs and maintenance requirements.Operational, design and construction experience is oftenavailable within the target countries. The systems can bebuilt locally at low cost, and the simplicity gives rise tobetter long-term reliability. The technology is technicallyHydropower implementationSuccessful implementation of hydropower in developing countriesdoes not finish with construction works: sustainable operation andmaintenance of small-scale hydropower must also be taken intoconsideration. A small-scale hydropower plant works in asustainable way when it is functioning and being used, when it isable to deliver an appropriate level of benefits (such as quality,quantity, continuity, affordability, efficiency), when it continuesover a prolonged period of time and when its management isinstitutionalized. Its administrative and replacement costs, as wellas its operation and maintenance, must be covered at a local levelwith limited but feasible external support. It also must notnegatively impact the environment.Therefore, before initiating a small-scale hydropower project theobjectives have to be clearly defined. Such objectives could includesocial infrastructure (provision of energy for health services,schools, drinking water), physical infrastructure (provision of energyfor irrigation systems, roads) and energy for the development ofsmall profit-making businesses. Also, capacity-building processessuch as teaching, training and awareness-raising are essential for asuccessful project although they take a lot of time. Local capacitiesto build, manage, operate and maintain micro-hydro plants reducecosts and are critical for sustainable success (see box 10.5 for anexample involving social problems in Sri Lanka).Regardless of ownership structure, the successful managementof micro-hydro plants requires a corporate structure that minimizesand commercially mature and small-scale hydro schemes canmake a useful contribution to rural electrification strategies,presenting a suitable alternative to decentralized dieselgeneration, particularly where fuel supply is a problem.There are, however, certain objections to ordisadvantages of small-scale hydropower schemes. Forexample, the cumulative direct costs (purchase of land,development costs) and indirect costs (environmentalpollution, population displacement) of adopting technologymay sometimes overwhelm the reasons for implementing ascheme. The scheme may also fail to satisfy the mergingenergy needs of the area and constrain industrialdevelopment and/or expansion. Certainly, microhydropoweroften faces unfair competition from highlysubsidized grid electricity, and from subsidized fossil fuels.political interference (e.g. from municipal authorities or powerfulcommunity members). The management is responsible for achievingclearly stated objectives related to financial situation, for coverage ofthe local grid system and quality (reliability) of the provided services.There are various reasons for technical and economic problemsof small-scale hydropower plants. A study on the functional status ofexisting micro-hydro plants in Nepal shows the following problems:■ poor site selection, inadequate/inaccurate surveys, wrongdimensioning, poor installations, faulty equipment;■ plants affected by floods and landslides;■ poor estimation of hydrological conditions, partly due to surveysconducted during rainy seasons;■ uneconomic canal length, bad canal design;■ neglect of civil works;■ owners’ inability to replace generators after breakdown; and■ inaccurate estimation of raw materials, demand and end-usepossibilities; oversized plants; overestimation of tariff collection;inappropriate rates; ignorance of competition with diesel.