I ran across a discussion about how many coal power plants are equivalent to 10GW of PV. I ran the numbers and below have posted the results. 10GW of PV is equivalent to 5 coal power plants. Many assume that coal plants average 1GW. But they actually average about 0.5GW. They also have surprisingly low capacity factor of under 70%. This means that when adjusted to 100% equivalent the average coal plant is about 376 MW or .376GW.
I was surprised to learn that in the Southwest, solar power plants are seeing capacity factors up around 25%.
Sources – Coal info – http://www.sourcewatch.org/index.php?title=Existing_U.S._Coal_Plants
Solar CF info – http://emp.lbl.gov/sites/all/files/lbnl-6408e_0.pdf