Hydropower Engineering

Hydroelectric Turbines: Harnessing the Power of Water to Generate Energy


As the world’s energy consumption explodes, no one can argue that there is a growing need to find an alternative to fossil fuels. The need for renewable, environmentally friendly power sources grows more apparent every day. Among the renewable resources being investigated and implemented is hydroelectric power. Hydroelectric power has proven to be a clean, viable renewable resource with many benefits.

Of all the renewable resources in the world, hydroelectric power is by far the most widely used. In fact, in 2005, an estimated 20% of the world’s electricity was supplied by hydroelectric power. That’s an impressive amount of power and should not be underestimated.

Hydroelectric power is generated through the use of a hydroelectric turbine. These turbines work by capturing the energy generated by the flow of water. As water is pushed onto the blades of the hydroelectric turbine, force is generated. This force acts through distance on the spinning turbine and results in a transfer of energy. Video below will give you a good understanding on how this happens.

There are two primary types of hydroelectric turbines in use today. Both types offer renewable, efficient sources of power but differ slightly in their function and use.

The majority of hydroelectric turbines in use are reaction turbines. This type is most commonly used in situations where there is a large volume of water passing consistently through the area; this is known as high flow. The reaction turbine does not require a high head of water. The water head simply refers to the height of the water level above the hydroelectric turbine. A low head means that the water has a small drop before entering the turbine. An excellent example of a high flow, low head area is a small dam on a fast moving river.

Reaction turbines operate as water runs from a tube through the turbine. As the water flows from the tube into the turbine, the water pressure is changed and this results in energy transfer. Due to the importance of water pressure in this process, the hydroelectric turbine must remain submerged at all times. This often requires that the turbine be encased in water if the water levels at the site are not consistent.

The second type of hydroelectric turbine is the impulse turbine. This turbine operates similar to a pinwheel. As water hits the blade of the turbine, known as a runner, the blade is pushed. Impulse turbines require conditions converse to the reaction turbine. These turbines are best suited to areas with a high head and low flow. Therefore, impulse hydroelectric turbines, while less common, fill a necessary niche that reaction turbines can not.


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