20GW is basically nothing next to the environmental damage it would cause by destroying the Mississippi delta in order to build this plant. 20GW gives you 480,000 MWh/d. The US as a whole is currently using over 13,000,000 MWh/d [1]. There is only one Mississippi! Not worth it, if you ask me.

Besides, it's not just biofilms that are the problem. With a river you're going to have huge amounts of silt and very fine clay clogging up your membrane. The maintenance costs for an installation like this would be overwhelming.

[1] https://www.eia.gov/realtime_grid/#/summary/demand?end=20160...

There is far more than just one US river. Hudson for example is: 21,400 ft³/s, Potomac is 10,810 ft³/s etc.

And the output is just mild salinity water, so you could probably extract form 1/2 the flow without causing that much environmental harm as long as you pipe the output to an area with similar salinity.

It's not the salinity I'm worried about, it's the installation.

Don't worry, it won't be installed and it's not practical. Also, the delta will be submerged by rising oceans soon enough so that won't be a worry either. :^(

Interesting ... curious what the replacement cost of these membranes are as compared to installation and ongoing maintenance of wind turbines.

Also, as always, curious how having these membranes in the water would affect the local ecosystem.

Have robots constantly cleaning surfaces. Then humans clean the robots.

Then use the salty water to clean the humans. The circle of life!