Hydropower 2.0 - Weird Ways to Generate Energy From Water

Humans have been generating power from water for centuries, using old-fashioned technology like water-wheels that use a stream's current to turn a mill for grinding grain. But with growing concerns about rising oil prices, dwindling resources and climate change, some clever thinkers are returning to water energy with new, and sometimes unusual, twists.

Researchers in France, for example, are studying how to generate electricity from falling rain. Their experiments show how raindrops can generate power by striking a piezoelectric material, which converts mechanical energy into electricity.

Or consider the innovation proposed by Leviathan Energy, which has developed a turbine system that generates energy from the flow of water through municipal pipes. Flushing toilets, surging sewage and rushing wastewater could all theoretically become new sources of energy.

Then there's the Woods Hole Oceanographic Institution's clean-energy, underwater robotic glider. The vehicle gets its power thanks to the variation of temperatures underwater: warm at the surface, cooler at depth. When the glider's in warm water, the wax in its engine tubes expands, converting heat energy into mechanical energy and pushing the device deeper into the water. As the vehicle dives, the water grows cooler, the wax contracts and that motion drives the glider back up into warmer water, where the cycle repeats.

"We are tapping a virtually unlimited energy source for propulsion," said Woods Hole oceanographer Dave Fratantoni.

Or how about the Free Flow Power Corporation's plan to plant a series of water-driven turbines in the Mississippi River from St. Louis all the way south to the Gulf of Mexico? The $3 billion proposal could end up generating enough electricity for 1.5 million homes, according to the St. Louis Post-Dispatch.

Researchers at Florida Atlantic University are studying a somewhat similar system that would capture energy from the powerful Gulf Stream flowing through the Florida Straits. The pilot project calls for large turbines to be placed deep underwater in the Gulf Stream's path. The research team believes each turbine could generate enough power for 500 homes. As a bonus, the Gulf Stream's chilly, deep layers could provide a much-needed source of cooling for Florida's steamy climate.

Bourne Energy is also exploring similar projects to generate energy from the flow of water in both rivers and oceans. The company says that, on a global scale, hydropower offers more promise than any other alternative energy source.

Finally, all you would-be inventors have a new incentive for coming up with a clean, safe way to generate energy from ocean power: a $20 million prize from the nation of Scotland. The so-called Saltire Prize was inspired by Scotland's natural riches in water and wind power, as well as by its leaders' goal of cutting greenhouse gas emissions in half by 2050.