Solar energy collection methods

The primary method used to collect solar energy and convert it into electricity is based on photovoltaic technologies. Solar panels that contain photovoltaic cells are installed in locations that maximize their exposure to solar energy. The cells are made up of a semiconductor material that generates a small amount of direct current when struck by the sun's photons. The cells convert the photons to electrons, which flow to an inverter that transforms the electricity to alternating current.

The production of thermal energy requires a process different from the photovoltaic technologies used to produce electricity. This collection method, referred to as concentrated solar power, uses multiple mirrors to reflect and concentrate the solar energy on a single receiver that contains a liquid such as oil or molten salts. The concentrated energy heats up the liquid to a high temperature. The liquid is then used to boil water and create steam, which drives a turbine generator that produces electricity. Because the liquid reaches such extreme temperatures, it can retain enough heat to boil water throughout the night.

Although photovoltaic and concentrated solar power technologies are the primary techniques used for solar power, they are not the only methods. For example, transparent photovoltaic glass has been installed in a number of buildings around the world. The glass lets light pass through the panes like a regular window but generates electricity in the process. Many buildings have also incorporated passive solar techniques into their design to reduce energy consumption. Some people are even building low-tech solar heaters from recycled cans to provide an inexpensive source of heat.