Hydroelectric generators. This is the generator hall in a hydroelectric power station. This large hall contains two generators (blue). Underneath the circular area around each generator is an inspection area. The blue structures are the tops of shafts that connect to a turbine below each inspection area. The hydroelectric power station is on a river - the turbines are rotated by water flowing through them. This rotates magnets in the generators, producing electricity. Photographed at the hydroelectric power station on the River Lule in Porjus, Sweden. Hydroelectric power, and other non-fossil fuel resources, form a large proportion of Sweden's energy resources.