Scientists at Ecole Polytechnique Fédérale de Lausanne have developed a new green energy technology based on osmosis. The idea itself is nothing new, and is the basis of electricity generation in hydrogen fuel cells:
“The concept is fairly simple. A semipermeable membrane separates two fluids with different salt concentrations. Salt ions travel through the membrane until the salt concentrations in the two fluids reach equilibrium.
What makes this discovery different is the cheap “fuel” (sea water) and the relatively abundant and naturally occurring molybdenum disulphide used to make the membrane:
“The system is used with seawater and fresh water, salt ions in the seawater pass through the membrane into the fresh water until both fluids have the same salt concentration. And since an ion is simply an atom with an electrical charge, the movement of the salt ions can be harnessed to generate electricity.”
According to the researchers, a one square metre membrane can generate 1MW of electricity – enough to power 50,000 energy saving lightbulbs.
Although still in development, if the technology can be scaled up, it could be quickly and easily deployed in estuaries around the world; adding significantly to the energy generated from renewable sources.