Energy | September 09, 2008 |
Scientists to Tap River Currents
An expert in electricity-generating "smart materials" and the author of 22 papers in refereed journals is searching for a way to harness the power of rivers without the ecological consequences of hydroelectric dams.
Dr. Lisa Weiland, Materials Science Professor at the University of Pittsburg, has come up with a gentle way to create what could be the next great clean energy supply for the world using piezoelectric ionic polymers.
Piezoelectric materials generate a slight electrical current when moved: in this case, by river currents and eddies.
Dr. Weiland is trying out the idea of using a flowing mesh of tiny strips of piezoelectric plastic, undulating like seaweed in the current of rivers and streams, up to 30 yards wide and about a mile long, to create electricity. The resulting electrical current would pass to small substations along the river's edge before charging a group of batteries to supply up to 40% of the electricity needed for a small town.
Her method likely wouldn't generate as much energy as a hydroelectric dam but would work with the river flow keeping the river intact and healthy. "There are other materials that give better performance or have higher energy densities," said Weiland, who is a published expert in "smart materials." But she is willing to sacrifice a little power to keep the ecosystem happy.
Dr. Weiland and her engineering students are now working out the best size, shape and array to test in the Kiskiminetas River, to supply the town of Vandergrift, near Pittsburg. An important consideration in the final design will be that they maintain the health and appearance of the river, which is used for fishing, canoe trips and other recreational activities. Once the array goes in on the riverbed, she said, "If you were able to look at it, you would just see a bunch of little things wiggling. It wouldn't look that different from a bunch of plant life."
According to Christopher Lynch, a smart materials researcher from the University of California, Los Angeles, this is the first freshwater hydroelectric power project of its kind. "The whole idea is very interesting," said Lynch. "Harvesting energy from rivers, ocean waves and currents are going to be an important segment of our overall energy generation in the future."
For centuries humans have dammed rivers and streams to grind grain and later, generate electricity. This could be the beginning of tapping into the power of flowing water more sustainably, using a more subtle technique. There are three and a half million miles of rivers in the nation, with towns along those riverbanks, and this small installation could supply as much as 40% of one town's electricity, so this could have wide applications.
From Mark Roth at the Post Gazette via Discovery News Image courtesy the Post Gazette