I'd say Sands End Imperial Wharf is the most likely destination. After that i'd say Earls Court or The old Unigate Factory at white city (but that may be too close to QPR).
Even so, I don't think chelsea would ever move south of the river.
The stadium would not be built in the power station, it would be built by land next to it. Whoever has made that mock up clearly hasn't read the proposals.