Solar Power

Solar power is about getting power from the sun's rays. That's simple enough. The sun's rays carry heat and light - plus radiation we cannot even see. But let's concentrate on the heat and light part, because that's the stuff we're going to harness.

When sunlight warms a stone wall in the corner of your garden it encourages heat-loving plants to flourish, that's solar power. When the sun's rays melt the snow in springtime, that's solar power as well. So solar power exists in nature. In fact none of us would be here if it wasn't for the sun's warming rays of sunshine...

The ancient Egyptians used mirrors to direct shafts of light deep into the access tunnels inside the Pyramids, and in the 1800s soldiers used mirrors for signalling long before electricity was discovered or invented. That was simple technology, on a par with having windows in your house to admit the outside daylight. Not rocket science.

Solar heating is obtained with the simplest of technologies, such as having a large mass (weight, density and thickness) of earth, bricks, concrete or stone to absorb heat during the day and release back it into the house all night. That is why solar homes have their main windows facing the noon-day sun in winter, and tend to exclude that same sun in the height of summer using house eaves or other shading devices.

Harnessing solar power to make solar hot water takes a little bit of technology, but not very much. After all, I'm sure you have noticed how cold water in a garden hose gets heated up by sunlight when it has been left standing in the sun for hours. You can go one stage better by building darkened metal water containers that catch the sun and heat the water inside. Two stages further and you can make solar hot water panels to heat the water and pipes to store it in an insulated water tank. But it's still simple physics that any handyman with a bit of imagination can put together.

But turning solar power into electricity takes some 20th or 21st century technological magic, the solar photovoltaic panel (or PV panel). This modern electronic device uses multiple solar cells, made of silicon, to turn the sun's rays into small amounts of electricity. All of the solar cells are wired together in combination to produce a required electrical voltage, which is usually a nominal 12 volts or 24 volts direct current (DC volts). Each solar panel is also rated for the number of Watts it can produce under ideal circumstances. A small pv panel might be 5 Watts, and a large one might be 160 Watts.

Most households will need an array of several solar panels to provide all the solar power electricity they will need. And if you use a lot of electricity, you can expect to spend several thousands of dollars on your home solar power system.