Turning sunlight into electricity

Abstract

The intensity of solar radiation in the Earth’s direction from the Sun is approximately 1353 kW/m², a number also called the ‘solar constant’. Accordingly, it is estimated that Earth receives about 96 billion kilowatts from the Sun each second. If this colossal and unlimited energy could be more fully utilized, our dependence on fast dwindling fossil cache will be drastically reduced. Solar energy is available in various forms such as direct solar radiation, wind, wave power, rain (in the form of hydropower), photosynthesis and ocean thermal gradients. Among these, the direct conversion of sunlight into electricity is clean and attractive. This article highlights various routes to directly harness electricity from sunlight.