Energy from the sun can be used to make electricity.

This video is from the U.S. Department of Energy's Photovoltaics Program and is narrated by actor Peter Coyote.

Solar cells are small, square-shaped panel semiconductors made from silicon and other conductive materials. They are manufactured in thin film layers. When sunlight strikes a solar cell, chemical reactions release electrons, generating electric current. Solar cells are also called photovoltaic cells - or PV cells for short - and can be found on many small appliances, like calculators, toys and even hats.

Individual PV cells are arranged together in a PV module and the modules are grouped together in an array. Some of the arrays are set on special tracking devices to follow sunlight all day long.

The electrical energy from solar cells can then be used directly. It can be used in a home for lights and appliances. It can be used in a business. Solar energy can be stored in batteries to light a roadside billboard at night. Or the energy can be stored in a battery for an emergency roadside cellular telephone when no telephone wires are around.

There are two primary PV markets. Off-grid systems are used where the cost of a PV system is cheaper than stringing electrical power lines long distances from the local utility. Grid-connected PV systems usually cannot compete directly with the cost of utility-produced power. Because of state incentives and federal tax credits, many people are considering grid-connected PV systems. If the PV system provides more power than the home or business uses, additional electricity is fed back into the grid for other people to use. This effectively spins an electricity meter backward.

Incentives offered to homeowners and small businesses is helping develop a more robust PV industry in the United States. Additional, growing demand for PV cells, along with competition, can help drive down the per watt price of PV cells while, at the same time, create new jobs.

Photovoltaics or solar cells can be purchased in two formats: as a stand-alone module that is attached to your roof or on a separate system, or using integrated roofing materials with dual functions - that as a regular roofing shingle and as a solar cell making electricity.

Because they do not produce polluting air emissions or water effluents, solar PV systems are prime candidates for supplying electricity at locations where such environmental impacts are unacceptable. For example, in parks and places where preserving high levels of environmental quality is important.