Note that we haven't yet reached the end of the line as far as improvements to the manufacturing process of solar cells is conscerned, in particular http://www.

Note that we haven't yet reached the end of the line as far as improvements to the manufacturing process of solar cells is conscerned, in particular http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature13435.html http://www.nature.com/nature/journal/vaop/ncurrent/abs/natur... . Cheaper solar energy might not be far off.