Freudenau power plant

The Freudenau power plant stands on the Danube in Vienna, the last of Austria’s ten Danube stations. Its concrete dam stretches for about 28 kilometres, lifting the river by 8.6 metres and storing 55 million cubic metres of water. Two parallel locks, each 275 metres long, let ships pass the dam without stopping. The plant’s six Kaplan turbines turn at 65.2 revolutions per minute and together deliver 172 megawatts. Every year they feed roughly 1,052 gigawatt-hours into the grid, enough for about 1.85 per cent of Austria’s electricity. A footbridge across the dam links the right bank to the Donauinsel, giving walkers and cyclists a Danube crossing. A bilingual plaque on the bridge marks the spot where eight crew lost their lives in 1996 when a ship was swept through a gate during high water. Inside the powerhouse visitors see the turbines turning beneath a 10.5-kilovolt generator. Nearby, the Stromhaus visitor centre uses videos and games to explain how the station works. Outside, the locks and weir create a wide stretch of still water that keeps the Old Danube and Lobau wetlands supplied. A side channel on the island lets fish swim past the dam, restoring some of the natural flow they once had.