As my colleague Mike Toman noted recently, Geoffrey Heal of Columbia University said the following in a recent blog post:
"neither costs nor capital requirement will prevent us from decarbonising the electricity supply. The real obstacle to doing this largely with renewables is our current inability to store power, and as long as we cannot store power we will need to use non-renewable sources like nuclear and coal with carbon capture and storage."
However, this view does not factor in future technological innovation, which I think is very significant.
The IEA Energy Technology Perspective projected that renewable energy could contribute around 50% of the power mix by 2050 under their Blue Scenario to achieve a 450 ppm world. Many other global leading energy/climate scenarios have the same projections, including those from Shell. Of renewable energy resources, geothermal, hydro, and biomass can provide base-load power. Indeed, solar and wind are intermittent.