Harnessing Solar Energy

Harnessing of Solar Energy: Photosynthesis versus Semiconductor Based Solar Cell Photosynthesis and semiconductor-based solar cells are both used to harness solar energy from the sun – photosynthesis for plants and semiconductor based solar cells for human beings. Photosynthesis consists of light reactions and dark reactions. It is a process in which carbon dioxide (CO2), water (H2O) and light energy are utilized to synthesize an energy-rich carbohydrate like glucose (C6H12O6) and to produce oxygen (O2) as a by-product. Simply put, photosynthesis is a process that transfers energy from the sun (solar energy) into chemical energy for plants and animals. Photosynthesis is a vital process among plants, algae and some bacteria that are able to create their own food directly from inorganic compounds using light energy so that they do not have to eat or rely on nutrients derived from other living organisms. A semiconductor-based solar cell is devised to convert light to electric current. The solar cell directly converts the energy in light into electrical energy through the process of photovoltaics (a field of semiconductor technology involving the direct conversion of electromagnetic radiation as sunlight, into electricity). Solar cells do not use chemical reactions to produce electric power, and they have no moving parts. Most solar cells are designed for converting sunlight into electricity. In large arrays, which may contain many thousands of individual cells, they can function as central electric power stations analogous to nuclear, coal-, or oil-fired power plants. The conversion of sunlight into electrical energy in a solar cell involves three major processes: absorption of the sunlight in the semiconductor material; generation and separation of free positive and negative charges to different regions of the solar cell, creating a voltage in the solar cell; and transfer of these separated charges through electrical terminals to the outside application