Paul Krugman has some optimistic economic commentary on solar energy in the NYT today, titled "Here comes solar energy".
It can not be emphasized enough, his points about indirect subsidies to dirty energy sources in the form of shifting the indirect social costs (health and environmental damage) of coal and fracking onto the public. The playing field is not level and tipped in precisely the wrong direction if we are serious about a better future for ourselves and the planet.
David Roberts has written two great pieces related to this.
On the various subsidies to the fossil fuel industries:
On conservative preference for the status quo: