Photovoltaic cells convert sunlight directly into electricity and are used as solar panels for 'clean' energy. Electrons become dislodged when they come into contact with sunlight, which in turn creates an electrical current. They are made essentially from silicon. The silicon used is 'doped' (it has a controlled amount of impurities placed into it) with boron or phosphorus which give up electrons when exposed to light.

The price of photovoltaic panels has gone down about 85% since the late seventies and can be found in anything from wrist watches to power communications equipment. After you buy it PV is the cheapest, simplest and cleanest to operate.

Larger and more complex rigs of PV are used all over the planet, from the polar ice caps to the tropics even in outer space on satellites.

So far PV only makes up a very small percentage of the energy make-up of any country. However, more and more people from individuals to large companies are beginning to use solar power as an alternate means of power. One of the main attractions for these people is the absence of moving parts, loud noises and a very clean source of power.

PV generally works better in areas with longer daytimes. The more exposure to sunlight the PV panels get, the more energy they produce. So if you place the solar panels closer to the tropics and have longer days then the exact same rig will not work as well in an area that has shorter days. The air temperature around the solar panels does not affect the ability of the PV in them to create electricity.

A dirty PV solar rig can reduce the rig's effectiveness about 20% over a hot summer. Cleaning of any PV rig should not be done very roughly and not more than once a year.