1. Cars, motorcycles, buses - Any actual "Smart City" would have abolished privately-owned transport in favor of public transport. It can be a mixed implementation of buses or
Personal Rapid Transit vehicles like
Pod Taxis. In either case the propulsion method can be replaced from Petrol/Diesel/CNG to Salt-water ( Ionic Liquid ) as demonstrated in
the Quant car. This will shake-up the petro-based world economy.
2. Factories - 3D Printing was meant to remove traditional factories from various processes to make products at personal or neighborhood level. This "make it when you actually want it" approach combined with socialist communes ( "from each according to ability, to each according to needs" ) will create a society where pollution is reduced to a large extent.
3. Power plants - Again, Salt-water-fueled power plants at device level, house level and neighborhood level can replace the current nuclear, hydro, solar, coal, oil plants. Also,
this vid from Pakistan is interesting, for it claims to generate free energy.
@Valar.