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this post was submitted on 01 Aug 2026
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Sounds cool. Naive question: you need many of them. Thousands or more. Is that not going to further slow down the river's current, which in consequence will provide less for the turbines further down the stream? And so on... There is no comment about that in the article.
The mass of earth provides arbitrary acceleration potential per unit of vertical drop, the roughness of the stream determines how much of that is converted into nonsense like hydropower or cool rapids that throw water in every direction.
What limits the density of turbines is a potential energy calculation frameable in terms of the minimum vertical drop between each turbine that still allows enough kinetic energy to be harnessed to make the practical engineering worth it.
Also turbulence in the immediate vicinty to the turbine is always going to increase entropy downstream making any energy extraction process less efficient past a certain density.
Lets think about that.
So, if what you assume were true, the flow speed would sink. The ingress flow rate would not reduce though, why should it, so the only way to keep the ratio between flow speed and cross section, aka the flow rate constant would be to increase the cross section area. So, the water level would have to rise, no other way to achive that. So the question is: "Will the river in its entire length raise its level when we put these turbines in at any point?" - that would be a great way to get hundres kilometers of deeper shipping lanes for free, but no, of course it won't.