The membrane has to be capable of dealing with a very high water "flex, " the amount of water that it is able to withstand being pumped across it, and at the same time, be fine enough to keep the salt and fresh waters separate.

FORBES: Getting Power From Salty Water

Fish and shellfish caught fresh from the waters of the Baltic and North Atlantic are served up daily at this fine restaurant, which also has an impressive wine list.

CNN: Sample a Swedish seafood smorgasbord