This is a cool article, thanks for writing it, but I'd question not being able to treat desert sand due the need to transport the energy needed there. One thing areas like that are not short of is energy, specifically the energy of the sun, we just need to know how to put it to use. After all, this is decrease of entropy rather than increasing it, so its something we should be looking for every opportunity to do.
Why would a solar furnace, coupled with usual PV solar farm, maybe backed by hydrogen fuel and food generation (see "solein" ), not be useful or practical for a desert based sand processing plant, capable of even maintaing temperate environment for workers and even plants, by fully sustainable clean aircon?
Would such a facility after setup, not be the definition of de-desertification?