Renewable energyRenewable energy is energy which comes from natural resourcessuch as sunlight,wind,rain,tides, and geothermal heat, whichare renewable (naturally replenished). About 16% of global finalenergy consumption comes from renewables, with 10% comingfrom traditional biomass, which is mainly used for heating, and3.4% from hidroelecticity. New renewables (smallhydro, modern biomass, wind, solar, geothermal, and biofuels)account another 2.8% and are growing very rapidly. The shareof renewables in electricity generation is around 19%, with 16%of global electricity coming from hydroelectricity and 3% fromnew renewables.
Types of renewable energy:• Wind power: wind• Hydropower: water• Solar energy: the sun• Biomass: organic material• Biofuel:solid biomass,liquid fuels and biogases• Goethermal energy: heat of the Earth• Wave power: the ocean
Wind power Wind power is the conversionof wind energy into a usefulform of energy, by usingwind turbines to makeelectricity, windmills formechanicalpower, windpumps for waterpumping or drainage, orsails to propel ships. The total amount ofeconomically extractablepower available from thewind is considerably morethan present human poweruse from all sources
HidropowerHydroelectricity is the term referring toelectricity generated by hydropower; theproduction of electrical power through theuse of the gravitational force of falling orflowing water. It is the most widely usedform of renewable energy. Once ahydroelectric complex is constructed, theproject produces no direct waste, and has aconsiderably lower output level of thegreenhouse gas carbon dioxide (CO2) thanfossilfuel powered energy plants.Worldwide, an installed capacity of 1,010GW supplied hydroelectricity in 2010.Approximately 16% of the worldselectricity is renewable, with hydroelectricityaccounting for 21% of renewable sourcesand 3.4% of total energy sources.
Solar energySolar energy, radiant light andheat from the sun, has beenharnessed by humans since ancienttimes using a range of ever-evolving technologies. Solarradiation, along with secondarysolar-powered resources such aswind and wavepower, hydroelecticity andbiomass, account for most of theavailable renewable energy onearth. Only a minuscule fractionof the available solar energy isused.
BiomassBiomass, as a renewable energy source, is biologicalmaterial from living, or recently living organisms .As anenergy source, biomass can either be used directly, orconverted into other energy products such as biofuel.
Biofuel Biofuel is a type of fuel whose energy isderived from biological carbon fixation.Biofuels include fuels derived from biomassconversion, as well as solidbiomass, liquidfuels and various biogases.Although fossil fuels have their origin inancient carbon fixation , they are notconsidered biofuels by the generally accepteddefinition because they contain carbon thathas been "out" of the carbon cycle for a verylong time. Biofuels are gaining increasedpublic and scientific attention, driven byfactors such as oil price spikes, the need forincreased energy security, concern overgreenhouse gas emissions from fossil fuels, and support from government subsidies.
Goethermal energyGeothermal energy is thermal energygenerated and stored in the Earth.Thermal energy is the energy thatdetermines the temperature of matter.Earths geothermal energy originatesfrom the original formation of theplanet (20%) and from radioactivedecay of minerals(80%).Thegeothermal gradient, whichis the difference in temperature betweenthe core of the planet and itssurface, drives a continuous conductionof thermal energy in the form of heatfrom the core to the surface. Theadjective geothermal originates fromthe Greek roots geo, meaningearth, and thermos, meaning heat.
Wave power Wave power is the transport of energyby ocean surface waves , and thecapture of that energy to do usefulwork— for example,electricitygeneration ,water destilation, or thepumping of water (into reservoirs).Machinery able to exploit wave power isgenerally known as a wave energyconverter (WEC). Wave power is distinct from thediurnal flux of tidal power and thesteady gyre of ocean currents. Wavepower generation is not currently awidely employed commercial technologyalthough there have been attempts atusing it since at least 1890. In2008, the first experimental wavefarmwas opened in Portugal, at theagucadoura wave park.