Stanford researchers have developed a battery that takes advantage of the difference in salinity between freshwater and seawater to produce electricity.
Anywhere freshwater enters the sea, such as river mouths or estuaries, could be potential sites for a power plant using such a battery, said Yi Cui, associate professor of materials science and engineering, who led the research team.
The theoretical limiting factor, he said, is the amount of freshwater available. “We actually have an infinite amount of ocean water; unfortunately we don’t have an infinite amount of freshwater,” he said.
As an indicator of the battery’s potential for producing power, Cui’s team calculated that if all the world’s rivers were put to use, their batteries could supply about 2 terawatts of electricity annually – that’s roughly 13 percent of the world’s current energy consumption.
The battery itself is simple, consisting of two electrodes – one positive, one negative – immersed in a liquid containing electrically charged particles, or ions. In water, the ions are sodium and chlorine, the components of ordinary table salt.
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