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Solar PV: How It Works
How Solar PV Works The Solar Cell The basic element of solar panels is pure silicon. When stripped of all impurities, silicon makes an ideal neutral platform for the transmission of electrons. Silicon atoms have room for eight electrons in their outer bands, but only carry four in their natural state leaving room for four more electrons. If one silicon atom contacts another silicon atom, each shares the other atom's four electrons creating a strong bond, but leaves room for eight additional electrons. Silicon atoms can combine for years to result in a large piece of pure silicon and is used to form the plates of solar panels. Two plates of pure silicon would not generate electricity in solar panels because there is no positive or negative charge. Solar panels are created by combining silicon with other elements that have positive or negative charges. Phosphorus, which has five electrons, is combined with silicon resulting in a negatively charged plate with one, unneeded electron. In order for electricity to flow, a positive charge must also be created. This can be achieved by combining boron, which has three electrons, resulting in a positively charged plate with one, unneeded electron. The two plates are then sandwiched together in solar panels, with conductive wires running between them. Energy Creation Sunlight sends out different particles of energy, one of which is called a photon. When the negative plates of solar cells are pointed at a proper angle to the sun, photons bombard the silicon/phosphorus atoms and knock off the extra (ninth) electron. The positive silicon/boron plate draws this electron into the open spot on its own outer band. As the sun's photons break off more electrons, the conductive wires pull the free electrons away from the plates and electricity is generated. The electrons that are not used or lost to the air are returned to the negative plate and the entire process begins again. Energy Transmission The energy created from the solar panel is direct current (DC) that needs to move through an inverter. The inverter chops the current to transform it to alternating current (AC) to meet grid frequency (60Hz in US). This allows the panels to sell electricity to the grid and “spin the meter backwards”. |
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