THE HISTORY OF PHOTOVOLTAIC TECHNOLOGY

The first solar cell was created in 1883. It was inefficient by today’s standards, converting only 1–2% of sunlight into electricity. The breakthrough in solar cell technology came in 1954 when researchers at Bell Laboratories stumbled across the photo voltaic (or PV) properties of silicon while experimenting with new transistor technologies. Three years later, PV research began in earnest to develop an independent solar energy source for space technologies. Thanks to continuing research, modern commercial PV cells have improved to 11–15% efficiency.

Historically, PV has been used extensively in areas that are not served by a power grid. As PV prices have dropped, and grid energy has become more expensive, PV systems are increasingly used in grid-tied applications.

A solar electric or PV cell uses a semiconductor material similar to that used in computer chips to absorb sunlight and convert it into electricity. Multiple solar cells are linked together to form a module or panel. Multiple modules/panels are connected to form a PV array.

There are three main types of PV panels: mono crystalline, poly crystalline, and amorphous silicon (thin film). A mono crystalline cell is the most efficient per area (produces the most power per square foot) and requires the most silicon. On the other end of the scale, amorphous silicon is the least efficient per area and requires the least amount of silicon. Most mono- and poly crystalline cells are uncased in a glass panel with a metal frame. Because amorphous silicon cells use less silicon, they are more flexible and can be used in a variety of applications, including a peel-and-stick panel that adheres to a standing seam metal roof.