"At some scale" does not imply "at our current scale." Our current energy use is a fraction of the energy we will be using 500 years from now, which really is not that far off in terms of human history.

I would imagine we will be using ~500x in 2516, a doubling every 55 years. All of earths deserts and more would need to be covered, even at 100% solar cell efficiency.

edit: global energy use has actually doubled every 20 years recently https://gailtheactuary.files.wordpress.com/2012/03/world-ene...