If you built a desalination system say… 500 feet under the ocean and have the pressure above pushing water through the filters, is it possible to lower the amount of required energy just a little? Then you’re more pumping water out of the system than pumping it through heavy filters
Wouldn't the energy of pumping the water all the way back up to the surface completely balance out the energy provided by the weight of that water to push it through the membrane?
