Solar electric panels turn light into electricity. They are commonly called "photovoltaic" (PV) panels because they generate a voltage from the energy in light. As daylight is abundant, PV panels offer a truly universal opportunity for clean energy. Although they will only ever be part of the solution, given that the sun regularly sets, they are an important part: tried, tested and reliable
Electricity from your roof
At the heart of a PV panel is a junction of two semiconductors, one positively charged and one negatively charged. The light that enters the panel bounces free electrons across the junction, creating an electric current. Using some smart electronics, this low voltage direct current is transformed into high voltage alternating current - the stuff we use every day in our homes
Despite the complexity of the technology, PV panels are very simple to use. Once they are installed on yur roof and plugged in, you can usually forget about them. There are no noisy moving parts wearing ut, no fuel or waste to lug around. Maintenance is minimal and the panels should last for decades (well beyond the 25 year warranty) as the solid state technology does not degrade.
Solar power and domestic needs
One of the few disadvantages of solar power is its poor match to our actual use of electricity at home. The sun is at its highest in the middle of the day when we need very little electricity, and absent altogether on winter evenings when the lights, television and ketle are all on. Happily this does not mean that PV panel owners have to go to bed at dusk - they simple switch to mains electricity instead. Most PV systems are fully intergrated with the national grid and owners are paid for the surplus they export.
Almost any roof or wall can generate electricity with a PV panel attached, but a pitched roof facing due south is best. South-east and south-west facing roofs are also suitable. You will get a decent output from a PV panel even under cloudy skies but direct sunlight pushes this output up to three- or four-fold. Ideally you want a site free from shadow-casting obstructions, but don't be put off if there is a little shading. Your roof must of course be strong enough to support the panels.