Look, there is no way in hell that you are going to be able to run a mining rig on Solar cost effectively. In fact if you just take a basic mining rig with a couple of 5870's in running at full, you would need to probably cater for around 750w continuous drain.

As you would only be able to get any sunlight during the day, you only have around 8 hours max (if you're very lucky) of any usable light. So to power it up you would need (in good conditions) around 20 80w panels. Hmm add that up. Ok, then you would need about 6 40w charge controllers (They're going to set you back around $150 each!!). On top of that, the batteries, the inverter etc,.... There is simply no way that this is worth it,...... Jeez, let's get real here. And if there was another way, then we would already know about it. Better off looking at fuel rods or something.