Now, scientists have used this tendency to create a power-producing membrane that can harvest electric current from nothing but salty water. By placing charged, thin membranes in between salty water and freshwater, scientists can create an expressway for the flowing particles, generating electric current. Now, researchers have developed a new kind of gatekeeper-a “Two-faced” membrane that has different properties on either side, from the size of the pores to the charge of the membrane itself. The researchers tested their Janus membranes with salty sea water on one side and fresh river water on the other. They found the devices were able to convert 35.7% of the chemical energy stored in the salty water into useable electricity. Next, the researchers plan to build larger membranes and see whether they can withstand the conditions of real sea and river water. If the membrane performs as well in “The wild,” the new membranes could be used to power remote communities with no other sources of renewable energy in just a few years, the researchers say.