Electricity generated at estuaries using light, osmosis

EPFL scientists are developing a method that can capture energy source that’s constantly available at river estuaries: osmotic power, also known as blue energy.

Electricity generated at estuaries using light, osmosisThrough this research, scientists have shown that using osmosis for power generation could be optimized using light. In the process of osmosis, molecules migrate from a concentrated to a more dilute solution across a semi-permeable membrane in order to balance the concentrations.

At river estuaries, electrically charged salt ions move from the salty seawater to the fresh river water. Scientists used this idea to harness this phenomenon to generate power.

To do so, they reproduced the conditions that occur at estuaries and shed light on a system that combines water, salt and a membrane just three atoms thick to generate more electricity. Under the influence of light, the system produces twice as much power as it does in the dark.

The system’s power generation potential depends on a number of factors which needs to be thin in order to generate maximum current. The nanopore allows positively charged ions to pass through while pushing away most of the negatively charged ones.

Michael Graf, the lead author said, “Essentially, the system could generate osmotic power day and night. The output would double during daylight hours.”

Scientists are now exploring possibilities to scale up production of the membrane, addressing a range of challenges such as optimal pore density. Still, there is a lot of work to do.