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HYDROELECTRIC ENERGY. Renewable Energy Resources 2008. António F. O. Falcão. HYDRO ENERGY RESOURCE Total resource: (about 15 times total world hydroelectric production Technical potential: about: Total world electricity consumption: 16 400 TWh. - PowerPoint PPT Presentation
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Renewable Energy Resources2008Antnio F. O. Falco
SOLAR ENERGY flux on the Earth surface:
About 25% consumed in evaporation of waterAlmost all this energy is released in water vapour condensation (clouds, rain) & radiated back into outer spaceOnly 0.06% remains as potential energy stored in water that falls on hills and mountains
Based on average output 1999-2002Source: G. Boyle, Renewable Energy, 2004.15,8% of world electrical energy consumption
Regional hydro potential output
RegionTechical potential TWh/yearAnnual output TWh/yearOutput as % of technical potentialAsia509357211%South America279250718%Europe270672927%Africa1888804,20%North America166866540%Oceania2324017%World14379259318%
Small hydroelectric plants (< 10 MW)World totalsInstalled capacity (GW) in small hydroelectric plants: China 26 Japan 3.5 Austria, France, Italy, USA > 2 each Brazil, Norway, Spain > 1 cada Portugal 0.3 (about 100 plants) TOTAL 50 to 60 GW
Installed capacity (GW)Annual production TWh/yearTotal (large + small)740 2700Small (< 10 MW)50 a 60 150Small/total6 a 7% 6%
Kaplan turbines (high )Usually: Low H Large Q
Kaplan turbineGuide-vane controlRotor-blade controlDouble control
Cross-flow turbine (also known as Mitchel-Banki and Ossberger turbine)Used in small hydropower plants.The water crosses twice (inwards and outwards) the rotor blades.Cheap and versatile.Peak efficiency lower than for conventional turbines.Favourable efficiency-flow curve.
Cross-flow turbine
ExerciseChoice of function F(q)Weibull distribution (widely used in wind energy):
kc0,50,500000,550,587400,60,664640,650,731920,70,790000,750,839880,80,882610,90,950401,01,000001,11,036361,21,063091,31,082751,41,097191,61,115361,81,124502,01,12838
Installed power: 22500 MW 34700 MW Francis turbinesThree Gorges Dam hydropower plant
Principais bloqueios ao desenvolvimento de PCHs na EU Processo de licenciamento Exigncias especficas locais Financiamento Ligao rede elctrica Venda de electricidade produzida Quadro regulador incerto Ausncia de informaes correctas Recrutamento e formao de tcnicos
Principais bloqueios em Portugal(FORUM Energias Renovveis em Portugal, 2002) Dificuldades na obteno de licenciamentos, sujeitos a um processo extremamente complexo, onde intervm, sem aparente coordenao, diversas instituies e ministrios. Dificuldade na ligao rede elctrica nacional por insuficincia da mesma e, ainda, por outras dificuldades processuais e operacionais. Ausncia de critrios objectivos na emisso de pareceres de diversas entidades e na apreciao dos estudos de carcter ambiental. Eventual opinio ou interveno negativa de agentes locais. Dificuldades de maios humanos na Administrao para tratamento dos processos de licenciamento. "Em 2001, a situao podia resumir-e a um impasse quase completo no licenciamento das PCHs" (situao pouco diferente da actual).
Aspectos econmicos Maiores alturas de queda so factor favorvel (menores caudais para a mesma potncia, menores custos de equipamento). Frequentemente maiores alturas ocorrem em zonas menos habitadas (consumo local, ligao rede). Na Europa, a maior parte dos melhores locais (maiores quedas) j esto aproveitados. Muito longo perodo de vida (frequentemente 50 anos) com pequenos custos de operao e manuteno. Investimentos nas grandes hdricas em geral do Estado. Mas a anlise econmica (investidores privados) baseia-se em amortizaes em 10 - 20 anos.
Basic bibliography (in addition to pdf files available at site of Renewable Energy Resources): Janet Ramage, Hydroelectricity, in: Renewable Energy (Godfrey Boyle ed.), Oxford University Press, 2004, p. 147-194. ISBN 0-19-926178-4. M. Manuela Portela, Hydrology, in: Guidelines for Design of Small Hydroplants (Helena Ramos, ed.), 2000, p. 21-38. ISBN 972-96346-4-5 (available at CEHIDRO, IST).
Explicar princpio de funcionamento; discutir a definio