UTILISATION & MANAGEMENT OF ENERGY SOURCES There are three mainly used sources of energy in Africa : i) Water for hydro- electric energy ii) Coal for thermal power iii) Sun for solar energy Other minor forms of power include Nuclear power (from uranium), Wind energy (wind), Tidal energy (sea waves), Biogas ( cow dung), Geothermal ( volcanic actvity), Natural gas (methane) etc. HYDRO-ELECTRIC POWER PRODUCTION (HEP) Moving water has kinetc energy which can be converted into electrical energy. The larger the volume of water the faster the water will fow and the greater the amount of power the water will produce. HEP Producton in Africa The amount of Hydro-electric power is fairly small though the contnent has the potental to produce more of this energy. Small producton is due to some factors such as : -demand for electricity is small -alternatve use of other sources eg. frewood, gas etc. -it is expensive -industrial demand is too small as industries are not fully developed -most water sources are internatonally shared -lack of capital -lack of skills and technology -politcal instabilites in some countries Factors infuencing HEP locaton and development -Steep gradient/fall/slope -Perennial supply of water -impermeable rock / non porous rocks -large market availability from industries and cites -frm rock foundaton/ solid geological base -deep, narrow gorge 1 HEP schemes in Africa -Owen Falls project (Uganda) -Cabora-Bassa dam (Mozambique) -Kariba dam (Zimbabwe/Zambia) -Akosombo/Volta river project (Ghana) -Kolwezi (Zambia) -Hendrik Verwoed (S. Africa) -Sennar dam (Sudan) -Kafue (Zambia) -Inga (DRC) -Tekeze dam project(Ethiopia) -Tana dam project (Kenya) -Koko (Ethiopia) -Jinja (Uganda) -Aswan dam project(Egypt) -Kainji (Nigeria) Generaton of power 2 -Water from the dam is made to fall down through PENSTOCK. - The force of falling water rotates the turbine. -The turbine drives the GENERATOR which produces electricity. Advantages of HEP -water is a renewable source of energy -very low maintenance costs/ low running costs -clean form of energy/ polluton free -higher producton capacity / it is more efcient -dam is mult-functonal eg. tourism/fshing/ irrigaton/industries etc. Disadvantages of HEP -expensive to construct/ very high inital costs -fooding -encourages water- borne diseases -displacement of people which is expensive -dam takes too much land which could be used for farming -alters natural fow of the river -siltng of the dam affects turbines -Species migraton/ destructon of animal habitat -disturbs the geological structure of the area eg. Earth tremors CASE STUDY ON KARIBA DAM PROJECT 3 Locatonal factors of Kariaa HEP scheme - perennial supply of water from Zambezi river. -narrow Kariba gorge is deep enough to provide a large head of water needed to generate HEP eg 95m -frm rock foundaton to carry weight of dam wall -steep gradient/ slope -impermeable rock/non porous rocks which reduce infltraton of water underground Reasons for development of Kariaa HEP -increased demand for electricity in the Zambian Copperbelt for smeltng and refning copper -increased demand for electricity in the Zimbabwean manufacturing and growing cites -To reduce the growing demand for coal from Hwange (Zimbabwe) -need for cheaper electricity Impact of Kariaa dam on the environment -fooding which displaced people, killed animals and destroyed natural vegetaton -reduced the volume of water downstream hence affectng water fow along the Zambezi river -it created food plains -weight of dam wall triggers earth tremors Importance of Kariaa Project on Zamaia/Zimaaawe -promotes self sufciency therefore cheaper electricity supplied to Zimbabwean industries and Zambian Copper mines -dam is multfunctonal eg. fshing/domestc use/water transport/food control etc. -provide infrastructure between Zambia and Zimbabwe eg bridge through dam wall -jobs/ employment/ income - foreign exchange through exports -Atracts other industries eg. Tourism -Training of locals/skills -diversifes the economy Why it is difficult to develop HEP in Botswana -few perennial rivers -Internatonally shared rivers -Porous rocks/ sandy soils -fat land/ few dam sites/ no steep slope/no deep gorge -markets are far from perennial rivers THERMAL POWER PRODUCTION (FROM COAL) Thermal power could be from coal, natural gas and petroleum. When it is from coal , the basic raw materials are water and coal. Conditons necessary for a Thermal power staton -staton should be located near a coal mine to reduce transport costs -nearness to a large source of water for cooling -place should be connected to other areas by rail or road -large, fat land 4 -nearness to large populated centres/ industries/ market Generaton of Thermal power -Coal is burnt to heat water -heated water changes into steam -steam at high pressure rotates the turbines -the turbines drive the generator which produces electricity -cooled steam turns into water or condenses Advantages of Thermal power -power staton can be installed anywhere since coal can be transported -alternatve source of energy/ reduces over exploitaton of natural vegetaton -Mining of coal encourages development of infrastructure -does not take too much land as compared to hydro electric power Disadvantages of Thermal power -coal is bulky/ heavy or difcult to transport -coal is non renewable source of energy -it is dirty -pollutes the atmosphere -high running costs eg. High running costs -very explosive nature of staton/ highly dangerous -difcult to dispose waste -low producton capacity/ inefcient CASE STUDY – MORUPULE POWER STATION Map of Botswana showing Morupule Power Staton ( include geographical features) 5 Reasons why the power staton was located in Morupule-Palapye: -presence of large deposits of coal -large land -fat land -water for cooling from Paje which is 45 km away -area is away from populated Palapye township -availability of ready market in towns eg. F/Town, Serowe, Palapye, S/Phikwe, Gaborone, Orapa -presence of North-South railway/ road -natonal power grid passes through Morupule making connecton of power to the grid easy Benefits of Thermal power staton to Botswana -lead to self sufciency in power producton/ reducton of import bill -has stmulated development of other industries -creaton of employment/ income to improve standards of living -reduced importaton of crude oil hence saving foreign exchange for the country -development of infrastructure for service delivery -training/skills development/ educaton for new jobs created -economic diversifcaton Proalems -destructon of the natural vegetaton/ deforestaton -air polluton -Coal is non- renewable source of energy 6 -running costs are high leading to expensive electricity to the consumers -coal is heavy/ bulky -coal is dirty -difculty in disposing waste SOLAR POWER (FROM THE SUN) Generaton of Solar Power -Solar panel with photovoltaic cells is exposed to sunlight -Rays from the sun are trapped by photovoltaic cells -The photovoltaic cells convert heat energy into electricity -Electrical energy is then stored in bateries for later use -The optonal charge controller controls the level at which the batery can be charged or discharged Advantages of Solar power -cheap to run/ cheap maintenance costs -clean/ polluton free -abundant/ readily available -renewable -fexible/ can be installed anywhere Disadvantages -expensive equipment/ inital costs are very high -intensity of rays varies according to cloud cover and seasons -delicate or fragile equipment -limited capacity/ low voltage Strategies used to conserve energy in Botswana -educaton -use of renewable sources of energy/ alternatve sources eg. solar power -tariffs -repair faulty electrical appliances -use of electricity- saving devices eg. Low voltage bulbs, automatc switches -switch off lights/ electric appliances when not in use -defrost refrigerators -load shedding -use smaller heatng plates for cookers 7 -enclose fre places 8
