Recent commercials produced by the fossil fuel industry claim that their products are necessary for light and heat. But the light and heat stored by fossil fuels originally came from the Sun. Why not cut out the middle-man and go straight to the source?

Solar energy can be harnessed directly for heating and indirectly for electricity. Passive solar design in architecture and engineering allows the warmth of the Sun to be captured in buildings and water systems, while photovoltaic cells use semiconductors to collect the energy of sunlight and channel it through electrical wires to power light bulbs, machinery, and all other electrical needs.

Passive solar design in architecture allows buildings to trap heat from the sun through a combination of windows and skylights that raise the daytime air temperature, as well as conductive building materials (bricks, masonry, etc.) that store heat during the day and release it slowly throughout the night.

Hot water systems can also be powered by solar energy. There are three types of solar hot water systems, all of which use the warmth of the sun to heat the water and/or pump it throughout a building. Active systems use solar energy to power water pumps. Passive systems use water temperature and gravity to create a process of natural circulation. Batch systems involve a tank that is directly heated by the warmth of sunlight. Solar hot water systems can be used to heat your house as well as fill your bathtub.

Solar lighting takes several different forms. Passive solar lighting, or daylighting, is the simplest form and can include skylights, windows, and light tubes, which reflect sunlight through a tube into rooms that do not have direct sun access. Photovoltaic cells can also be used to power light bulbs.

Until recently, making photovoltaic cells was a very expensive and difficult process that made installing and using solar panels almost more costly, both energy- and finance-wise, than using electricity from fossil fuel sources. Recent advances in technology have made solar panels cheaper and more energy-efficient. Photovoltaic cells, from the ones in rooftop panels to those in large commercial solar arrays, all work in the same way: they collect light particles, or photons, and channel their electrons into a system of wires as electricity. This electricity can then flow directly to your outlet and into your toaster or hair dryer.

The major drawback of solar power is that it doesn't work at night, unless the energy is stored somehow (either in heat-absorbing materials or in some sort of battery). Like wind power, there must be something to fill in the in-between times when light isn't shining.

Source: Wikipedia, the free encyclopedia