PV systems

Power from the sun is a great idea. Cheap and almost continuous (especially in southern areas) sunlight can be used to provide electricity for everything from calculators to city blocks.

One key to getting electricity from sunlight is a device called a photovoltaic cell, or PV cell. PV cells are found on calculators, sidewalk lighting systems, rooftops, and along highways to power emergency phones.

PV systems have been around for a long time. It has been known since 1839 that certain materials can produce electricity when exposed to sunlight. It wasn't until the 1970s, though, that research spurred by the space program resulted in commercially viable solar power systems.

Today, PV cells can be used to provide almost all the electricity needed by a typical household. They can be installed on rooftops as well as integrated into windows to provide non-polluting electrical power.

PV systems can be used to provide all of the power needs of a household, or it can be integrated with traditional power sources. People living in remote areas that don't have access to affordable electricity find an alternative with PV systems. Increasingly, people living in urban areas can use PV systems in conjunction with regular power grids. If their solar cells generate more electricity than needed the excess is fed back into the power system reducing their power costs even more.

There are two types of solar cells available -- standalone modules or integrated roofing materials. Both are installed on the roof of the house, but the integrated solar cells have the appearance of regular roofing shingles.

PV systems cannot be used everywhere. They must be installed where there is unobstructed sunlight for most of the day. They are most effective in southern areas which sunshine most of the year. They are very popular in California, Australia, and Japan.