I studied one such concept, by SkyStation international (CEO: Alexander Haig) which used a "Corona Ion Engine" invented by a UCLA physics prof named Wang.
Its 1400-Newton "Corona Ion Engine" developed about 314 pounds of thrust and was used to keep the blimp hovering above on spot on the earth for use as a communications platform.
It used solar cells on the surface of the blimp to develop power. I found that ~600 kW were potentially available, but they quoted only 50kW. This was laughably underpowered and would be soaked up almost entirely by the engine.
The engine approximated an "actuator disc" of aerodynamic propulsion theory. It was highly efficient (using little power per pound of thrust) but also could not develop high thrust levels, even if all 600 kW were available.
Just FYI, jets and rockets ("thermal engines") require roughly 20 kW (thermal) per pound of thrust. Non-thermal engines do somewhat better, but using electricity to move a giant blimp around would still be S - L - O - W.
--Boris
--Boris