Bitcoin mining by using solar energy. Is it possible? I have a peculiar question concerning about bitcoin mining, for example, in Brazil it is unfeasible due to the high cost of electric power. Is it possible to do mining by using solar energy?
Does someone know how much energy is necessary to setup a basic unit of bitcoin mining? 
It sounds interesting for me, since solar energy is cheap! Of course you will have the investment with batteries, solar panels, cables, etc..  but I think it still possible..  any ideas?

EDITED

I'm looking for a basic project about mining bitcoin using solar energy.
It largely depends on what machine you want to power with those solar panels. You're definitely going nowhere with GPU based mining. As PCs consume a huge lot of energy, and those who don't, are equipped with Atom and Intel graphics, meaning mining won't get you far with that equipment.

However, it may be possible to run a USB ASIC miner based on a Raspberry Pi. I think those kind of machines consume very little energy. However, you may also need an Internet connection, but I'm assuming you already have a router you can connect to.

In that case, I'd buy one Raspberry Pi for each USB ASIC stick you want to buy.

The initial cost may be a bit hefty, though, and I'm not sure the performance would be that great, because there's just so much hashing power already in the Bitcoin network.

I'm sure you're better off mining Litecoin, Dogecoin or Feathercoin anyways. But well, there's no USB ASIC miner for scrypt cryptocurrencies, so you're out of luck for those alts.