Floating solar systems have enormous potential. They cost more than solar systems on land, but they are more efficient. But the legal situation in Germany is strict, as it is still unclear whether they affect the lake ecosystem.
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00:00Solar systems on water, a technology with a future.
00:04They are more expensive than solar systems on land, but more efficient due to the water's cooling effect.
00:12The first floating solar system in Germany was installed on a quarry pond in 2019.
00:19The biggest project being built is in an open cast mining area in eastern Germany.
00:24Lignite was mined here for decades.
00:26It's the size of 20 soccer fields, power for 8,000 households.
00:32The Hohlmanns gravel plant is one of the pioneers in Germany.
00:36The size of their floating plant, 3.3 hectares, around 5 soccer fields.
00:41They use the electricity it generates for the gravel works.
00:46In a gravel plant like this, all the large extraction equipment, including the processing equipment that sifts the sand and coarse gravel from the fine gravel,
00:55all run on electricity.
00:57The plant is about 40% self-sufficient, which means we are about 40% independent.
01:05In times like these, when there is little sunshine, we have to buy additional electricity from the grid.
01:14Solar systems depend on sunshine, which varies with the seasons and time of day.
01:19Since the gravel plant doesn't run on the weekends, the electricity generated gets fed back to the grid.
01:26But feeding it into the grid doesn't make any economic sense for us,
01:30which is why we're currently considering whether it might be better to invest in storage technologies.
01:37The gravel works has invested 5 million euros of its own money in the floating solar plant.
01:42The state provides no subsidies.
01:45There are still hurdles in the approval process, which takes about two years.
01:53It's simply a process where many authorities themselves don't quite know how to deal with the issue.
02:03The first floating solar plant was built in California in 2008.
02:07Countries such as Switzerland and Britain followed suit.
02:11Today, the biggest in Europe is in the Netherlands.
02:14Globally, however, China is leading the way and runs the world's highest capacity power plant on a flooded coal mine.
02:22In Germany, a law was passed in 2023 that only allows floating solar installations on artificial lakes.
02:29Only 15% of the lake can be covered, with a distance to the shore of at least 40 meters.
02:36The Water Resources Act is more or less a precautionary law,
02:40which is intended to prevent negative environmental impacts and negative effects on the ecology of water bodies.
02:51We've noticed that they don't have these regulations in the Netherlands, for example,
02:56that they actually have waters with coverage of around 70%.
03:01That means they want to take full advantage of this boom.
03:09What impact could floating solar panels have on the lake's ecosystem?
03:16It could be that if the oxygen supply to the water were to change dramatically,
03:21algae growth would decline, or it would die off.
03:24Phytoplankton would die off, and the fish would no longer find enough food.
03:28Maybe they wouldn't have enough oxygen either. We just don't know.
03:34One condition for the construction of this plant was to document the changes in the lake.
03:44We commissioned a biological engineering firm to do this.
03:48We have to use almost all the tools available to us.
03:51We have to actually prove what effects this plant has on water chemistry,
03:55phytoplankton, mussels, aquatic plants, bottom-dwelling gravel algae,
04:00resting birds and impact victims.
04:03And we have to demonstrate the results over five years at four test sites each.
04:09Floating solar systems last around 20 years.
04:12Insurance and mortgages have to be paid.
04:16In the future, floating solar systems that combine wind and water power plants are also planned.
04:22The technology will be particularly interesting on the high seas.
04:26However, they will have to withstand extreme wind, waves and salt water.