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Japan has opened its first osmotic power plant

(www.theguardian.com)
301 points pseudolus | 1 comments | 25 Aug 25 02:53 UTC | HN request time: 0.491s | source
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Johnny555 ◴[26 Aug 25 17:44 UTC] No.45029856[source]▶
Does it generate enough electricity from freshwater to offset the energy used to desalinate more water? Would it be more efficient to just treat the freshwater that would have been used to run the plant for drinking water and desalinate less water?
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1. throwway120385 ◴[26 Aug 25 19:38 UTC] No.45031271[source]▶
If you're using water at the end of a process that's just going to get mixed anyway, you're just extracting waste energy from the mixing process. Basically the fresh, used water and the highly saline water are in a lower-entropy state, and normally we'd just dump both in the ocean and allow the entropy to increase without extracting energy. But in this case we allow their entropy to increase in a controlled environment and so we're able to extract some energy in that process.