Yes, I'm pretty sure that the blue disc is an extensive network of solar paneling. Given the hippy-ish nature of the FH inhabitants, and the necessity of providing plenty of energy with little surface area to build power plants on (and being cut off from energy sources on the mainland), it seems fitting that FH would power itself through enviornmental means. The FH introductory FMV also shows a network of wind turbines, which most likely also serve as energy producers.


As for crossing the lake, how did any people on our own planet cross lakes? Boats and rafts seem easy answers, especially given the natural buoyancy of a salt lake. Given the technological advancement of the Estharian culture, however, I think any kind of craft probably would have sufficed.

And the bridge? As Big D said, the FF8 world's ocean floor seems to work in favor of building such structures. I'm assuming that the ocean floor is relatively flat and probably not all that deep (Deep Sea research center is a RELATIVE term, after all. It could be deep for them but relatively shallow compared to Earth's oceans). Why do I say shallow? Well, there are a number of reasons, such as no craft larger than the Gardens takes to the seas and there seems to be little evidence of giagantic sea creatures, but the biggest reason is the underwater railroad system. I forget where - correct me if I'm wrong - but I recall one railroad going underwater and coming back up somewhere else - Balamb to Timber perhaps? In any case, there is a reason that we don't have transatlantic railroads. The English Chunnel is feat enough. If such a thing is possible, than the ocean's depth and floor flatness is probably workable enough to construct the bridge.

Finally - a mobile FH? I don't think so. Why didn't they submerge to escape Galbadian attacks? Also, submerging would cut them off from 1. Their energy supply, which is solar and wind powered, and 2. Their material supplies - which are imported from Galbadia and Esthar along the horizon railroad. I'm not sure it can detach itself from the bridge either - the railroad network seems pretty well integrated into the town.