Redstack uses Salinity Differences to Generate Electricity
97.5 percent of Earth’s water contains salt. Since the water itself is being explored as a source of electricity, it is only reasonable to take a close look at the abundant resource presented by the salt in that water. Reverse electrodialysis (RED) does just that.
Reverse electrodialysis (RED) is a technology that allows electricity to be generated using water of different salinity as the source. The process relies on a stack of alternating ion-selective membranes that passes through either the positive sodium ions from fresh water or the negative chlorine ions from salt water.
The stack of waterproof membranes includes sealed chambers as well as titanium electrodes wrapped with precious metals to improve conductivity located at the positive and negative posts of what is essentially a salt battery. When water of different salinity is pumped into the chambers, the positive and negative ions flow past each other in different directions towards the positive and negative electrodes. This creates a potential electrical difference from which power can be generated.
(View more from NewScientist)
Dutch company Redstack plans to build a pilot salt battery in the northern Netherlands region where there is ready access to North Sea saltwater and fresh water from an inland lake. This facility would produce 5 kilowatts, with the potential for 50 kilowatts within a few years.