Solar Electric (Photovoltaic)

Photovoltaic (PV) devices generate electricity directly from sunlight via an electronic process that occurs naturally in certain types of material, called semiconductors. Electrons in these materials are freed by solar energy and can be induced to travel through an electrical circuit, powering electrical devices or sending electricity to the grid.

PV devices can be used to power anything from small electronics such as calculators and road signs up to homes and large commercial businesses.

SEIA Fact Sheet - Solar Photovoltaics

History

The PV effect was observed as early as 1890 by Henri Becquerel, and was the subject of scientific inquiry through the early twentieth century. In 1954, Bell Labs in the U.S. introduced the first solar PV device that produced a useable amount of electricity, and by 1958, solar cells were being used in a variety of small-scale scientific and commercial applications.

The energy crisis of the 1970s saw the beginning of major interest in using solar cells to produce electricity in homes and businesses, but prohibitive prices (nearly 30 times higher than the current price) made large-scale applications impractical.

Industry developments and research in the following years made PV devices more feasible and a cycle of increasing production and decreasing costs began which continues even today.

Present Status

In 2007, the U.S. solar energy industry saw a promising future. The U.S. is the current world leader in the manufacture of both next-generation thin film technologies and the polysilicon feedstock used in most PV applications. U.S. PV manufacturing grew by 74 percent in 2007 and U.S. PV installations grew by 45 percent - both among the fastest growth rates in the world. Globally, the U.S. is the fourth largest market for PV installations behind world leaders Germany, Japan and Spain.

Most modern solar cells are made from either crystalline silicon or thin-film semiconductor material. Silicon cells are more efficient at converting sunlight to electricity, but generally have higher manufacturing costs. Thin-film materials typically have lower efficiencies, but are simpler and less costly to manufacture. A specialized category of solar cells - called multi-junction or tandem cells - are used in applications requiring very low weight and very high efficiencies, such as satellites and military applications.