Photovoltaics are a form of renewable energy generation, termed “Active Solar” energy.
The Photovoltaic (PV) effect is a process by which photons cause electrons to eject from inside a semiconductor, such as silicon.
PV cells, also known as solar cells, are made of very thin wafers of silicon with trace amounts of other metals. When sunlight hits these cells, electrons are pushed out of the silicon molecules, which are collected and fed in the same direction to produce DC electricity.
The cells are arranged onto solar panels, which make up solar arrays. These arrays can be connected to an existing electrical grid or to batteries which store the energy for later use. Solar cells are safe and quiet, don't have moving parts, require little maintenance, produce no pollution during operation, and last as long as a conventional fossil fuel power plant. The semi-conductive material can be rigid or flexible, attached to roofs, walls, or incorporated into building materials.
What are the benefits of photovoltaics?
Fairly high net energy yield; works on cloudy days; very quick installation; easily expanded or moved; no CO2 emissions; low environmental impact; last 30-40 years; low land use (if on the roof or built into windows or walls); reduces dependence on fossil fuels; fairly low-cost.
What are the drawbacks?
Need access to the sun; moderate efficiency; need to be tied to the power grid or energy storage; environmental costs not included in market price; high land use (solar-cell power plants) disrupt desert areas; DC current must be converted to AC.