Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency.
I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exercise". Our inability to store energy is not just some side concern that will go away any time now. There is a reason carbon fuels are so prevalent - their energy density is far above what we can store in batteries. Without scalable and high density energy storage, unpredictable energy sources like solar or wind are much less useful because often there is no sun or wind at high demand and on the contrary there can be an overproduction during low demand. Germany already causes serious headaches for the European grid when it floods the network with electricity on sunny/windy days. They actually have to pay other countries to take over the extra capacity.
Solar, wind, tidal etc... energy are all awesome and clean (if we disregard the land that they take up), but there are many difficult issues that remain to be solved before they can become a core part of the energy production.