Most people think of hydropower as an old technology that hasn’t changed significantly in many years. A company called Natle Energy has come up with a new design for a turbine. The turbine is the part that generates the power.
How do turbines work?
You can have turbines that work just from the flow of a river or tidal flow, but normally there is a dam that holds back the water. Then you use the energy contained in the falling water to generate electricity. The way this works is that some or all of the water going down river is channeled into a channel or tube called a penstock. This focuses the water on a turbine. Turbines have different designs depending on the amount of flow and the amount of head. Head is the height which the water falls. But basically, a turbine has blades that the water pushes against and causes it to turn.
Some of the turbines look like propellers, some look like the blades in jet engines. There are several variations, but they haven’t changed that much in decades.
Once the water is turning the turbine, a shaft from the turbine is connected to a generator and causes that to turn. The generator is what generates the electricity.
Problems with Turbines
One of the problems with turbines is fish. Any fish coming downstream that go through the turbine are usually killed. One reason is simple physical trauma. But another is less obvious, pressure change. Fish are very sensitive to pressure changes and the pressure change can be very abrupt and sudden as a fish goes through the turbine which can be deadly. That is why many dams have fish ladders to allow the fish to go around the dams.
Fish ladders and sometimes fish elevators (if the dam is very high) are not always very effective. That is where Natle Energy has come up with an interesting solution. It can decrease the cost of the turbine and at the same time is much more friendly to fish.
Venetian Blind Turbine
The Natle Energy turbine looks kind of like a Venetian blind that has been made into a loop and turns around a top and bottom axle. The water flows through the side moving up, pushing it up and then because of the curve of the blade in the Venetian blind the flow angles down and pushes down the “blind” blades on the back side of the loop. So the water works twice, pushing the front side of the loop and pushing down the back side, making it rotate faster.
This turbine would be used in low head situations. Other turbines for low head situations such as the Kaplan or propellers or Hydromatrix are not fish friendly. The neat thing about the Natel Energy turbine is that it is fish friendly and they are smaller, lower cost and generate the same amount of power. The fish can swim right through a Natel Energy turbines without a problem. Neat new technology.