One of Cui's concerns is finding a good material for the negative electrode. He used silver for the experiments, but silver is too expensive to be practical.
His group did an estimate for various regions and countries and determined that South America, with the Amazon River draining a large part of the continent, has the most potential. Africa also has an abundance of rivers, as do Canada, the United States and India.
But river water doesn't necessarily have to be the source of the freshwater, Cui said.
"The water for this method does not have to be extremely clean," he said. Storm runoff and gray water could potentially be useable.
A power plant operating with 50 cubic meters of freshwater per second could produce up to 100 megawatts of power, according to the team's calculations. That would be enough to provide electricity for about 100,000 households.
Cui said it is possible that even treated sewage water might work.
"I think we need to study using sewage water," he said. "If we can use sewage water, this will sell really well."
|Contact: Louis Bergeron|