It cannot be used during night and not all the light from sun can be trapped
Solar energy is one the alternative energy source that is used most widely across the globe
it is also used for drying clothes, used by plants during the process of photosynthesis and also used by human beings during winter seasons to make their body temperature warm. Solar energy can be extracted either by Solar Thermal or using Photovoltaic (PV) Cells. Learn more about these methods here. - See more at: http://www.conserve-energy-future.com/AlternativeEnergySources.php#sthash.gwCiG4IW.dpuf