Water for people.pdf - WHO Thailand Digital Repository

2 6 2 / 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 NeedsOther Forms of Water/EnergyGenerationOcean energyThere are three known types of ocean energy generation. Tidalenergy is transferred to oceans from the Earth’s rotation throughgravity of the sun and the moon and is the most advanced in termsof use, with a number of commercial plants. Wave energy ismechanical energy from wind retained by waves, and ocean thermalenergy is stored in warm surface waters that can be made availableusing the temperature difference with water in ocean depths.Box 10.6: Hydropower in NepalIn Nepal, 85 percent of the population lives in rural areas.The national electrification rate is 13 percent, but above 80percent in the cities. The electrification rate provides alarge market for micro- and mini-hydro schemes. Thepower forecasts prepared by the Nepal Electricity Authority(NEA) foresee that 30 percent of the national householdswill be connected to the grid by the year 2020. Ruralelectrification develops mainly by the extension of thenational grid in the southern lowlands, the Terai, where 40percent of the national population will be living around2005. In the inaccessible hill and mountain regions,electrification is achieved primarily via isolated grids.Nepal has a feasible hydropower potential of around80 GW. The political and expert opinion concerning thebest strategy for the use of this potential and thepromotion of national electrification is divided into twocamps. One side argues for development of large-scalehydropower destined for exports to India with attachednational grid electrification. Others argue that the primaryHowever, this technology is still far from being mastered, and assuch is an untapped source of energy.Geothermal energyGeothermal energy is generally defined as heat stored within theearth. The earth’s temperature increases by about 3°C over100 metres in depth. Two types of geothermal energy generationcan be taken into consideration for practical application indeveloping countries: hydrothermal, which is hot water or steam atmoderate depth (100 to 4,500 metres), and geothermal heatpumps. Table 10.5 presents the advantages and disadvantages ofvarious forms of energy.focus of hydropower policy should be on the developmentof micro-hydropower. The latter technology is said to berelatively low-cost, to reply to a nationally manufacturedtechnology, and would be well-suited to provide energy forthe population in the isolated hills and mountain regions.Sixty-three of Nepal’s seventy-five districts havepotential for hydropower application. With the support ofinternational NGOs since the 1970s, Nepal has succeeded inbuilding up an industrial sector capable of manufacturing orassembling all micro-hydropower components except thegenerators for micro-turbines up to 300 kW. The governmentsupported the development of micro-hydro through varioustechnical and financial support programmes. It is estimatedthat the economically viable micro-hydro potential in Nepal isabout 42 MW. The cost of stand-alone plants is in the rangeof US$1,200 to 1,600 per kilo watt (in 1993 dollars).The installed capacity of micro- and mini-hydropower ispresented below, showing the actual use of micro-hydrogeneration.Installed micro-and mini-hydropower in NepalTotal Mechanical Add-on Electricity InstalledTechnology number purposes electricity only capacity (MW)Ghatta 1 25,000 25,000 1 0 12Peltric sets 2 250 250 0.25Micro-turbine 3 950–1,000 800 150 30 9–10Mini-turbine 4 36 36 8.51 Traditional water mill 2 0.5–3 kW integrated turbine and generator sets 3 >100 kW 4 100–1,000 kW.Source: Based on Mostest, 1998