Kudos for the idea and this huge potential source of energy.
Also as far as I know, the United States never claimed sovereignty over the moon. That means other countries are free to improve Earth with scientific endeavors on the moon. But what happens if some one wants to put offensive or defensive weapons on the moon. Who could stop them?
source: http://www.dailymail.co.uk/sciencetech/article-1390682/Plans-gigantic-lunar-ring-solar-panels-beam-energy-Earth-unveiled.html?ITO=1490