Solar Power Singularity

Back as early as the energy crunch of the 70s I have been reading about when various alternative energy technologies would be economically feasible to replace fossil fuel. These levels have always been exceeded, without much happening in alternatives. I remember $50 a barrel in particular as a holy grail level that would cause all sorts of infrastructure to change. Surprise, not much has happened. Now TCS suggests that the solar energy singularity is at hand.