Solar power has a major drawback: it only works part of the day. In most locations, energy production drops significantly after a few hours, and vanishes entirely at night. This means solar can only be used during the day, and therefore cannot be used for primary base generation. There are two strategies for overcoming this problem: store excess energy for use during off-peak hours, or transmit excess energy from areas in peak hours to areas in non-peak hours. Neither strategy has been very feasible--batteries are inefficient, and global(!) transmission lines are prohibitively expensive.
So this is cool: Store solar heat in molten salt. It's not a slam dunk solution, but it's definitely better than anything else anyone's come up with.