It is cheaper because the membrane pressure requirements are much lower than seawater because the salt concentrations are  much lower--- maybe 25% of seawater, or less. Seawater is fairly cold except in places like the Persian Gulf. Even elsewhere too because it will be pumped from fairly  deeper sea areas. I imagine a way around it for wells would be  to first pump to an above ground  storage tank so it will be warmed somewhat. Solar heat can  help.

Published by

It is cheaper because the membrane pressure requirements are much lower than seawater because the salt concentrations are  much lower--- maybe 25% of seawater, or less. Seawater is fairly cold except in places like the Persian Gulf. Even elsewhere too because it will be pumped from fairly  deeper sea areas. I imagine a way around it for wells would be  to first pump to an above ground  storage tank so it will be warmed somewhat. Solar heat can  help.