US Department Of Energy is leading a new research program to reduce the cost of solar power generation to a commercial equivelant of one dollar per watt generated by 2017 and to make Solar power less expensive than fossil fuels by 2020. The link below leads to a good article about this research and process.

http://www.renewableenergyfocus.com/view/19395/sunshot-solar-pvs-falling-costs/

The site,  www.renewableenergyfocus.com requires you to register (its free) for access to this to a great deal of other information about all forms of renewable energy.