Drawbacks of Turbines

An environmental issue that has not been solved in the transition from hydro electric power in dams to damless hydro power is fish mortality. As fish pass through a dam’s water intake and into the turbine the fish would often be killed. The blades of the turbine striking the fish could easily kill them. Additionally, the change in pressure from the water intake though the turbine and out the spillway is a causes of the mortality. In the tested damless turbines, fish mortality is still an issue. Manufactures are striving to develop fish friendly turbines. The water flow through the turbine creates a suction and if a fish swims too near it will be sucked into the turbine and potential be struck by one of the blades. In addition to the turbines that are designed for the ocean currents that are generally constantly flowing, there have been turbines designed to harness the power of ocean tides. However, there are few locations where tidal barrages, as this concept is called, can be implemented. Furthermore, at the locations where tidal barrages are a viable option the tide would only be able to power the turbines for 10 hours of the day due to the ebb and flow cycle of the tides. On the other hand, tides are very consistent and thus easily predictable which could allow for other options to be functioning during the times when the tides are not moving in or out.

Locations of River Turbines

The Mississippi River is the home of the “nation's first commercial hydrokinetic turbine, which harnesses the power from moving water without the construction of a dam.” Specifically, the river turbine was placed in the Mississippi River near Hastings, Minnesota. The turbine, capable of producing 35-kilowatts, was “positioned downstream from an existing hydroelectric-plant dam and — together with another turbine to be installed soon — will increase the capacity of the plant by more than 5 percent” (4). The design used in today’s wind farm’s turbines has been altered to function similarly underwater. These underwater wind farms or tidal turbines “are propelled by tidal currents instead of wind” . New York City’s East River is the site of the “largest test of this new type of power production” (11). The six 35-kilowatt turbines with 16 foot diameter rotors which spin as close as six feet from the water’s surface are “scheduled to be installed by mid-March in a channel that's off-limits to large vessels”. During the testing phase the turbines will “provide power to a supermarket and a parking garage.” Based on the results of the testing the Virginia-based company “Verdant Power hopes to add hundreds more turbines, potentially reaching a total capacity of as much as 10 megawatts — enough to power 4000 homes” . The East River testing “should answer real-world questions, such as whether the rotors will become encumbered by barnacles” . If the viable river and estuary turbine locations are made into hydroelectric power sites “researchers estimat[e] that [the United States’] rivers and estuaries could provide up to 130,000 gigawatt-hours per year — about half the yearly production of the country's dams” .