Sun holds a great deal of energy within itself. The planet receives so much energy from sun in the form of its light and heat that it can power the whole world for years to come. The solar energy can be tapped by collecting its heat or by converting its light into electricity. This can be done by installing solar panels or solar power plants. The solar power plant or photovoltaic cells are made up of silicon alloys, which absorb photons emitted from the sun. The photons hit the silicon atoms in the PV cells, transferring their energy and releasing the electrons from their orbit around the nucleus, thereby generating electricity.

The solar power plant, on the other hand, uses mirrors to reflect the heat energy from a large area onto a small space, such as a pipe filled with a fluid. Once the fluid's temperature has been raised to hundreds of degrees, it can be used to boil water and produce steam for a conventional generator.

Solar thermal investments have increased over the years. The number of solar cells manufactured has risen by 50% in 2007, with its total installed capacity reaching 8.7 GW. The efficiency of these cells has also risen from 4% in 1982 to over 20% for the latest technologies.

I'm sorry, I had to remove the link because only users that are active on the forum can post them, to avoid hit-and-run advertisement.
All that you said is very interesting, and I already knew it was a growing energy. Only thing is: are the initial costs still very high?

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Zidanie
Yes that was probably and advertisement. However I had a friend who was selling solar systems in Italy and he told me that whatever you invest the Italian government gives you back more but in 20 years. He said that the hardest part of his job was to convince people that the Italian government would actually pay that sum. I personally have a solar hot water system and other green improvement in my house. In the US it works differently : you get a part of the expense back immediately from the state of Maryland ( in my case ) and the rest is apparently tax deductible -

This is an example on how it works :
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Attention Maryland Residents:

You are now eligible for substantial Maryland Solar Cash Rebates and Federal Solar Tax Credits. The Maryland Energy Administration is releasing the first round of Fiscal Year 2010 Maryland Solar Rebate Offers (up to $10,000 cash each) this week.
In addition, the end of 2009 is rapidly approaching. A new 30% Solar Federal Income Tax Credit is now in effect. If you install your solar electric system in 2009, you will receive 30% of the installed system cost back in the form of an income tax credit when you file your 2009 Federal Taxes.