We would have to entirely cover the earth with Solar panels and the sun would have to shine 24/7 to supply our energy needs .
Not really. About 10,000 square miles would do for present US energy needs. About the size of VT and NH together, but preferably located somewhere in say, AZ.
The contiguous US is over 3M square miles, so the 10,000 would be about .3% of the US.
That whole day/night bit would still be a problem, though.
http://www.instituteforenergyresearch.org/energy-overview/solar/