Finding Potential Sites for Small-Scale Hydro Power in Uganda: a ...

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and generator is 65% and 80% efficient respectively, then the calculation to determinethat schemes power potential will be as follows:1. Net head:0.25 ⋅ 60 = 15m60 -15 = 45m2. Hydraulic power:45 ⋅ 10⋅9.81=4414W3. Mechanical power:4414 ⋅ 0.65 = 2870W4. Electrical power:2870 ⋅ 0.8 = 2295W or 2.3kW3.2.3 Environmental AspectsSmall-scale hydro is one of the most environmentally benign methods of powergeneration and the most significant environmental consideration is that it does not haveany kind of emissions, which usually are associated with conventional energy resources.However, small-scale hydro is not totally without environmental problems (Fraenkel etal. 1991).To begin with, even if the small-scale hydropower scheme itself does not generate anyemissions, there are still some emissions associated with the technology during other lifecycle stages. The chain of manufacturing processes required to manufacture andconstruct the generation and transmission equipment, e.g. penstocks, turbines, generatorsand cables, are a important source of emission (IEA, 1998). A study was performed inNorthwest of America, to calculate emissions from the manufacture of materials used inconstruction of hydropower schemes. The study calculated the atmospheric emissions ofcarbon dioxide (CO 2 ), sulphur dioxide (SO 2 ), oxides of nitrogen (NO x ) and particulatesper unit of material manufacture of steel, concrete, copper and aluminium for a site witha total capacity of 40.8 MW. The results show emission values of 8.6 g/kWh of CO 2 ,0.025g/kWh of SO 2 , 0.068g/kWh of NO x and 0.005g/kWh of particulates (ORNL/RfF,1994). These emissions are significantly less than those arising from conventional fossilfuel stations. For example, they have approximately half the direct emissions from a newbuild coal power station, with flue gas desulphurisation (EC, 1995). It should also beemphasized that the example is a relatively large project and is likely to represent theupper limit of emissions for most small-scale hydropower schemes (ORNL/RfF, 1994).20
Further, the quality of the water in a river or stream connected to a small-scalehydropower scheme can be affected in numerous ways, amongst others through changesin suspended solids. Impounded water generally becomes sediment heavy, whereasdischarge water is sediment deficient. The disruption of natural flow patterns may causeincreased deposition or erosion, which can affect species and agriculture downstream(IEA, 1998).The presence of small-scale hydropower has in many cases a negative influence of fishmigration, in particular migratory salmonids, e.g. salmon and sea trout. The scheme cancontribute to increased fish mortality both direct through creation of obstructions to thefish migration and indirect because the diversion also affects the invertebrate populationin the river; this can reduce food sources for organisms up the food chain, including fish.The impacts on fish migration can be minimised in a number of ways, e.g. through theuse of fish passes to allow the upward migration of fish or the installation of grids acrosswater intakes and tailraces which prevents the entry of fish into the turbine (IEA, 1998).There are several more environmental considerations such as; habitat change, impact onecology and irrigation but most of these impacts are small, localised and often reversibleand they can often be ameliorated or avoided by use of various methods or approaches(IEA, 1998).3.2.4 Small-Scale Hydropower Status, Potential and CostsTo get small-scale hydropower into the context of total installed energy capacity it issuitable to first review the hydropower sector as a whole. In this section the referenceWEC is abundantly used, even though it is rather old we consider the figures to berepresentative in order to get an opinion of the present conditions. According to WEC(1994) hydro plants accounted for a capacity of 627 GW, which is 22.9% of the world’stotal installed, electric generating capacity. The combined output was 2281 TWh, whichis 18.4% of the world total electricity production. Industrialized countries accountbroadly for two-thirds and developing countries for one-third of this hydropowerproduction. The statistics for regional small-scale hydropower capacity and productionare given in Table 3.2. The estimated installed capacity of small-scale hydropower wasabout 19.5 GW in 1990, or 3.1% of world hydropower capacity. Annual output forsmall-scale hydropower is 81.7 TWh, which indicates that it accounts for 3.8% of hydroelectricity production.21
Page 1: Seminar series nr 121Finding Potent
Page 5: AbstractOver 2 billion people, most
Page 9: AcknowledgmentsFirst of all, we wou
Page 12 and 13: 5 Result ..........................
Page 14 and 15: For the specific case of Uganda, a
Page 17 and 18: 2 Study AreaThe main reason for us
Page 19 and 20: In the 1960’s Uganda was one of t
Page 21 and 22: 2.1.3 TopographyMost of Uganda is s
Page 23: Figure 2.4 The highest volcano in K
Page 26 and 27: e able to manually write the data,
Page 28 and 29: Depending on the appearance of the
Page 30 and 31: o Then the water flows from the for
Page 34 and 35: Table 3.2 Capacity and production o
Page 36 and 37: Table 3.5 Small-scale hydropower ca
Page 38 and 39: technology was supplied to an area
Page 40 and 41: component to all of these issues, g
Page 42 and 43: The Rural Electrification project t
Page 44 and 45: The closer the interviewer is to th
Page 46 and 47: Over this area we bought the follow
Page 48 and 49: The primary erosive force determini
Page 50 and 51: There are a set of tolerances used
Page 52 and 53: ivers are seasonal, since the hydro
Page 54 and 55: (a) (b) (c)Figure 4.8 An example sh
Page 56 and 57: 4.2.6 Post Processing of Output Dat
Page 58 and 59: A = ( b ⋅ h)2(4.3)Where A equals
Page 60 and 61: elinquish because of too expensive
Page 62 and 63: The first step when performing the
Page 64 and 65: more obvious in their geographic co
Page 66 and 67: By using a smaller area it is possi
Page 68 and 69: 5.3 Summary of Resultso The general
Page 70 and 71: projects are supposed to be finance
Page 72 and 73: Sinks are a reoccurring problem whe
Page 74 and 75: UTM Zone 36N projection. The study
Page 76 and 77: As described in chapter 3.3.3 all r
Page 78 and 79: and if good financing possibilities
Page 80 and 81: Hutchinson M. F., Dowling T. I., 19
Page 83 and 84:
9 Appendix9.1 Interview: Rural Elec
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9.3 Digital DataAll data layers are
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Frame creationThis is made in order
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Site 16 (147486,78619)Site 20 (1560
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