The concept, dubbed Flohara, was created for the Morocco Pavilion of the 2014 Venice Biennale, and would be suitable for other similar desert climates. Though referred to as a city by XTU, it looks more like a large group of basic shelters rather than the kind of sprawling urban center that a city usually brings to mind.
The basic idea of creating homes in the desert using sand sounds great, and it's not the first time that this kind of idea has been presented. XTU's concept is remarkably similar to Magnus Larsson's vision for a desert-based habitable wall, aptly named Dune. It's also reminiscent of the tech behind Dupe, but without the pee.
XTU imagines using light, inflatable, and easily-transported "bubbles" as support skeletons for building upon. These bubbles would either be shipped to the location needed or created locally by some kind of unspecified machinery.
Once in place and duly inflated, the bubbles would then be positioned toward the wind. Sand, water and a hydrogel would be added to Sporosarcina pasteurii (a bacterium that solidifies sand), prepared into a mixture, and sprayed onto the bubbles. They would then be left in place for the shifting sand and sun to slowly build and harden the structure before the bubble was deflated and work started on the next shelter. Or that's the theory anyway.
Surprisingly perhaps, solar power is not mentioned in the proposal (nor power of any sort), but the shelters would feature a deep well system that provides water for cultivating vegetables and other greenery, making a veritable oasis in the desert. The shadow cast by the wall-like shelters is also put forward as a positive by the architects, and XTU reckons this could aid cultivation.