Renewable energy

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Renewable Energy RENEWABLE ENERGY Renewable energy sources – solar, wind, biomass, geothermal and hydro – could make important contributions to sustainable development. Currently, their exploitation in commercial markets is low, being constrained by costs and uncompensated benefits (externalities), as well as intermittent supplies and other technical and institutional considerations. But they hold promise for: enhanced energy security by providing supplies that are abundant, diverse and indige
  Renewable Energy   3 RENEWABLE ENERGY  Renewable energy sources – solar, wind,biomass, geothermal and hydro – couldmake important contributions to sustainabledevelopment. Currently, their exploitation incommercial markets is low, being con-strained by costs and uncompensated bene-fits (externalities), as well as intermittent sup-plies and other technical and institutionalconsiderations. But they hold promise for:  enhanced energy security by provid-ing supplies that are abundant,diverse and indigenous (non-importdependent), with no resourceexhaustion constraints;  reduced global and local atmospher-ic emissions when used in place offossil fuels;  improved options to meet specificuser and infrastructure needs, partic-ularly in rural areas and in newlyindustrialising and developing coun-tries; and  increased local and regionalemployment opportunities in energyinfrastructure manufacturing, installa-tion and maintenance for developedand developing countries alike.Over the next twenty years economicallyrecoverable renewable resources will increase as a result of cost reductions from techno-logical improvement and expanding markets, and new market valuations (e.g., of carbonemissions). Environmental concerns have increased the attraction of these sources topolicy-makers and growth in demand in industrialised countries is leading to economies ofscale. Such growth enables increased access by the developing world.Some renewable technologies are now commercially available and cost-competitive in par-ticular market circumstances, but most are still at an early stage of development and tech-nologically not mature. Their costs remain high, but are continuing to fall. Further reduc-tions are needed for them to compete broadly with the cheapest fossil-fuel alternatives. SITUATION AND OUTLOOK In 2000, renewable energy sources provided 1371Mtoe, about 13.8 per cent, of theworld’s primary energy supplies. Biomass (1048Mtoe) and hydropower (226Mtoe)  What are renewableenergies  Although the terms hydro-electricity, solar and  wind power can be easily understood,other terms are less common. Bioenergy  covers a wide spectrum of ener-gy activities from direct production of heat through combustion of fuel wood and otherbiomass residues, to the generation of elec-tricity, and the production of gaseous andliquid fuels and chemicals. It is widely usedglobally. In developed countries, it usuallyinvolves the combustion of biomassresidues for heat and electricity. In devel-oping countries, biomass in the form of  wood and agricultural residues is often themost common fuel for cooking and heat-ing. In North and South America, the pro-duction and use of ethanol in transport isan established and growing option.The geothermal resource is the internalheat of the earth. Its use covers a range of options from power generation to spaceheating and/or air conditioning. One of the advantages of geothermal energy isthat it is viewed as a base-load power, i.e.not faced with the concerns of intermittent supply.  4 dominated the supply. Rural household bioenergy use was estimated at 510Mtoe. Non-OECD countries use much more renewable energy than OECD countries; 22.4 per cent oftheir primary energy demand, compared with 6.2 per cent in the OECD. Renewable ener-gies contribute significantly to the energy mix of many countries. Figure 1. Total Primary Energy Supply from Renewable Sources, 2000 Source: IEA Statistics. Production of primary energy from renewable sources is expected to grow rapidly overthe next two decades. Nonetheless, their share in the global energy mix will probablyremain small in the absence of further cost reductions and determined government inter-ventions. The reference case of the IEA’s World Energy Outlook projects that all renew-able energy use in developing countries (including hydro and “non-commercial” com-bustible renewables and waste) will increase by 35 per cent (see Table1). But their shareof total developing country energy demand will decline from 26 per cent in 1997 to 18per cent in 2020. The global share of renewables in energy use is projected to declinefrom 14 per cent in 1997 to 12 per cent in 2020. These are baseline projections thatcould change with the adoption of new policies.Hydropower met 3 per cent of the world’s primary energy needs in 1997 and is currentlythe world’s second largest source of electricity (about 20 per cent of total generation) aftercoal. The world is expected to be using some 50 per cent more hydroelectricity by 2020.The largest increases are in developing countries, where it is expected to be the fastest-growing renewable energy supply. Growth, particularly in the OECD regions, is limited bythe availability of suitable sites and environmental considerations. Solid BiomassHydroOtherSolid BiomassHydroOtherOECD (328 Mtoe - 6.2% of TPES)Non-OECD (1043 Mtoe - 22.4% of TPES) WorldOECDNon-OECDPrimary Solid Biomass76.4%44.0%86.6%Hydro16.5%34.4%10.8%Geothermal3.2%9.0%1.4%Municipal Wastes1.3%5.5%<0.05%Industrial Wastes0.8%2.4%0.3%Liquid Biomass0.8%1.1%0.7%Biogas0.5%1.8%0.1%Solar Thermal0.3%1.0%0.1%Wind0.2%0.8%<0.05%Tide, Wave and Ocean<0.05%<0.05%<0.05%Solar Photovoltaic<0.05%<0.05%<0.05%  Commercial biomass, wind, solar and other non-hydropower renewables are expectedto be the fastest growing primary energy source in OECD countries, with an annualgrowth rate averaging 2.8 per cent over the next two decades. Most of the growth isexpected to come from wind and bioenergy, supported by policies and measures tocurb greenhouse-gas emissions and to diversify the energy mix. Despite this stronggrowth, the share of non-hydro renewable energy in the global energy mix will reachonly 3 per cent by 2020 because of the current low starting point (2 per cent of world’senergy mix).Table 1. Total Primary Energy Supply of Renewable Energy by Region (Mtoe) Note: Figures do not include bioenergy in developing countries.Source: IEA (2000), World Energy Outlook 2000  , OECD/IEA. RENEWABLES AND THE ENVIRONMENT The environmental impacts of renewable energy are site specific, but generalisationsare still possible. Renewable energy is usually more environmentally friendly thanalternative energy sources, especially with regard to air emissions. The likely life-cycleemissions (taking into account fuel cultivation, harvesting, collection, transportationand processing, as well as power plant construction, operation and decommissioning)from main renewable energy technologies and conventional electricity generation areshown in Tables2 and 3. The results are purely indicative but show the variations andrelative differences between the various fuel inputs. Life-cycle emissions from renew-able energy use are small compared with those from fossil fuel plants. The studiesupon which the figures are based did not examine nuclear energy. Though nuclearpower generation does have a major environmental impact, it releases no sulphurdioxide (SO 2 ) or nitrogen oxides (NO x ) and little carbon dioxide (CO 2 ). Its life cycleemissions of these gases falls within the ranges shown for non-hydroelectric renewableenergy. 5 19972020World 410697 OECD 286434 ã Europe 106190 ã North America 150191 ã Pacific 3053 Transition Economies 2332 Developing Countries 101231 ã China 1756 ã East Asia 1549 ã South Asia 920 ã Latin America 5391 ã Middle East 24 ã  Africa 611
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