Tierr@_de_N@die: The storage costs are the big issue regarding renewable energies since you don't have this energy in the right moment you need it then it must be stored it in order to have enough power when demanded. This innovative idea from the MIT could resolve the problem.
The new design stores heat generated by excess electricity from solar or wind power in large tanks of white-hot molten silicon, and then converts the light from the glowing metal back into electricity when it’s needed. The researchers estimate that such a system would be vastly more affordable than lithium-ion batteries, which have been proposed as a viable, though expensive, method to store renewable energy. They also estimate that the system would cost about half as much as pumped hydroelectric storage — the cheapest form of grid-scale energy storage to date.
Source (news.mit.edu): “Sun in a box” would store renewable energy for the grid