It seems that despite the new Smart Grids (a new type of grid that leverages on communication technology, allowing to save energy by better managing supply and demand) without a cheap and efficient mechanism to store energy, the role of renewables as a major component of the world's energy mix is still far from reality.
The intermittence of renewable energy sources (like wind and solar) is still a major factor that calls for a technological breakthrough that would allow to store energy in times of low demand and advance towards the replacement of fossil fuel energy generation.
Check out this article on FT.com
here
