When people think about aggressive renewables programs and the rapid growth of solar or wind, they typically expect mention of northern European countries such as Denmark and Germany.
But the U.S. is making huge strides in introducing renewables, as cost comes down, way way down.
An excellent report by the highly respected Union of Concerned Scientists about solar power's growth and potential in the U.S. can be found here.
In contrast to Japan, where solar power = solar PV, the report also discusses concentrating solar power (CSP), those huge collections of mirrors in the desert aimed at a tower, where heat is used for electricity generation. CSP has the benefit of being less "intermittent" than PV. These installations can continue to provide power well into the evening, covering the entire peak demand period without additional storage.