Brief Intro to renewable energy

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Brief Intro to Renewable Energy
Renewableenergyisgenerallydefinedasenergythatcomesfromresourceswhichare naturally
replenishedonahumantimescale suchassunlight,wind,rain,tides,wavesandgeothermal heat.
Renewableenergyreplacesconventional fuelsinfourdistinctareas:electricitygeneration,hot
water/space heating,motorfuels,andrural (off-grid) energyservices.
Basedon REN21's 2014 report,renewablescontributed19percenttoour energyconsumptionand
22 percentto our electricitygenerationin2012 and2013, respectively.Both,modernrenewables,
such as hydro,wind,solarandbiofuels,aswell astraditional biomass,contributedinaboutequal
parts to the global energysupply.Worldwide investmentsin renewabletechnologiesamountedto
more than US$ 214 billionin2013, withcountrieslike Chinaandthe UnitedStatesheavilyinvesting
inwind,hydro,solarand biofuels.
Renewableenergyresourcesexistoverwidegeographical areas,incontrasttootherenergysources,
whichare concentratedinalimitednumberof countries.Rapiddeploymentof renewableenergy
and energyefficiencyisresultinginsignificantenergysecurity,climatechange mitigation,and
economicbenefits. Ininternationalpublicopinionsurveysthereisstrongsupportforpromoting
renewable sourcessuchassolar powerandwindpower.Atthe national level,atleast30 nations
aroundthe worldalreadyhave renewableenergycontributingmore than20 percentof energy
supply.National renewableenergymarketsare projectedtocontinue togrow stronglyinthe coming
decade andbeyond.
While manyrenewableenergyprojectsare large-scale,renewabletechnologiesare alsosuitedto
rural andremote areasand developingcountries,where energyisoftencrucial inhuman
development.UnitedNations'Secretary-General BanKi-moonhassaidthatrenewableenergyhas
the abilitytoliftthe poorestnationstonew levelsof prosperity.
Powergeneration.Renewableenergyprovides21.7% of electricitygenerationworldwideasof 2013.
Renewablepowergeneratorsare spreadacrossmanycountries,andwindpoweralone already
providesasignificantshare of electricityinsome areas:forexample,14% inthe U.S. state of Iowa,
40% inthe northernGerman state of Schleswig-Holstein,and49% in Denmark.Some countriesget
mostof theirpowerfromrenewables,includingIceland(100%),Norway(98%),Brazil (86%),Austria
(62%),NewZealand(65%),andSweden(54%).
Heating.Solarhotwater makesanimportantcontributiontorenewable heatinmanycountries,
mostnotablyinChina,whichnowhas 70% of the global total (180 GWth).Most of these systemsare
installedonmulti-familyapartmentbuildingsandmeetaportionof the hotwater needsof an
estimated50–60 millionhouseholdsinChina.Worldwide,total installedsolarwaterheatingsystems
meeta portionof the waterheatingneedsof over70 millionhouseholds.The use of biomassfor

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heatingcontinuestogrowas well.InSweden,nationaluse of biomassenergyhassurpassedthatof
oil.Directgeothermal forheatingisalsogrowingrapidly.
Transport fuels.Renewable biofuelshave contributedtoasignificantdecline inoil consumptionin
the UnitedStatessince 2006. The 93 billionlitersof biofuelsproducedworldwidein2009 displaced
the equivalentof anestimated68 billionlitersof gasoline,equal toabout5% of worldgasoline
production.
As of 2011, small solarPV systemsprovide electricitytoafew millionhouseholds,andmicro-hydro
configuredinto mini-gridsservesmanymore.Over44millionhouseholdsuse biogasmade in
household-scaledigestersforlightingand/orcooking,andmore than166 millionhouseholdsrelyon
a newgenerationof more-efficientbiomasscookstoves. UnitedNations'Secretary-General BanKi-
moonhas saidthat renewable energyhasthe abilitytoliftthe poorestnationstonew levelsof
prosperity.
At the national level,atleast30 nationsaroundthe worldalreadyhave renewableenergy
contributingmore than20% of energysupply.National renewable energymarketsare projectedto
continue togrow stronglyinthe comingdecade andbeyond,andsome 120 countrieshave various
policytargetsforlonger-termsharesof renewableenergy,includinga20% targetof all electricity
generatedforthe EuropeanUnionby2020. Some countrieshave muchhigherlong-termpolicy
targetsof up to100% renewables.OutsideEurope,adiverse groupof 20 or more othercountries
target renewableenergysharesinthe 2020–2030 time frame that range from10% to 50%.
Climate change andglobal warmingconcerns,coupledwithhighoil prices,peakoil,andincreasing
governmentsupport,are drivingincreasingrenewableenergylegislation,incentivesand
commercialization. Newgovernmentspending,regulationandpolicieshelpedthe industryweather
the global financial crisisbetterthanmanyothersectors.Accordingtoa 2011 projectionbythe
International EnergyAgency,solarpowergeneratorsmayproduce mostof the world'selectricity
within50 years, reducingthe emissionsof greenhouse gasesthatharmthe environment.
Renewableenergysources,thatderive theirenergyfromthe sun,eitherdirectlyorindirectly,such
as hydroand wind,are expectedtobe capable of supplyinghumanityenergyforalmostanother1
billionyears,atwhichpointthe predictedincrease inheatfromthe sunisexpectedtomake the
surface of the earthtoo hotfor liquidwatertoexist.