What is Solar Power?

Solar power is energy that is captured from sunlight. Solar energy can be harnessed in two ways: by converting the energy in sunlight into electricity via photovoltaic systems, or by converting the energy in sunlight into heat, via thermal systems. Solar power systems are very scalable, from small household systems to immense power plants.

Photovoltaics, or PV, is a technology that takes advantage of material properties to convert the energy of photons from sunlight into electrical current. Most solar panels are made up of cells of silicon wafers assembled into a grid. Solar cells are grouped together into modules, and modules are grouped together into a complete panel. Tiny solar panels can be used to power electronic devices, such as calculators, and huge arrays of solar panels can be used to produce electricity for large building complexes.

Silicon is the primary material used in solar panels, and has an efficiency of about 15%.  Other advanced materials called "thin film" solar cells can achieve higher efficiencies; potentially up to 30%.  However, thin film solar cells are more expensive to manufacture at this point in time.

Solar thermal power systems use reflectors to concentrate sunlight onto a single location and heat up a working fluid. The working fluid is used to power a steam turbine generator. Unlike photovoltaics, solar thermal systems have the ability to store some energy by storing the heated working fluid until the energy is needed.

Solar thermal systems have three primary configurations: trough, parabolic, and flat panel.

• Trough reflectors are long curved reflectors that look like a portion of a pipe. The curved surface reflects sunlight to a collector that looks like a thin pipe running through the center of the trough.
• Parabolic reflectors are large circular mirror assemblies that reflect sunlight to a central collector.  Parabolic reflectors look like satellite dishes.
• Flat plate reflectors are used in very large reflector arrays to reflect sunlight to a tower in the center of the array.