Delayed response here but....Mr Troll...year average insolation is 5.25 WHours per day per sq metre at my latitude.
Go here to check for wherever you live NASA website
http://eosweb.larc.nasa.gov/cgi-bin/sse/grid.cgi?uid=3030
that gives about 3000 KWHours per day falling on your 6000 sq ft roof.
Present day solar efficiency is still fairly low (could be much higher if we were serious about it) see this link for a simple idea that improves cost effectiveness hugely
http://www.greenandgoldenergy.com.au/
Even at a low 20% conversion efficiency 600KW hours per day oughta be enough for even the greediest energy hog.
Imagine how much cheaper and more efficient solar energy could be if a tiny fraction of the money spent on nuclear research was spent on alternative energy instead.