The penetration of PV Solar Power is significant today and Solar Power is very fascinating from the source point of view.
However, it is questioned how sustainable this is. The link below gives a good discussion of the critical elements from the perspective of sustainability.
http://www.lowtechmagazine.com/2015/04/how-sustainable-is-pv-solar-power.html
Though the PV panel efficiency increases, the manufacturing technology improves and the percentage of energy consumed from renewable energy may increase, are the requirements of sustainability met?