Hydroelectric Turbine Types

Are you planning to install a hydropower system? It may be for your home or for commercial purposes. One of the key components that make up this system is the hydro turbine. It plays a pivotal role in facilitating the generation of electricity.

It is also important to know that there are different types of hydropower turbines. The core purpose of this article is to highlight the main types of hydro turbines. At the end of it, you will be able to select the best type that will be suitable for your power generation needs.

What are hydropower turbines?

Let’s start by defining the hydro turbines. These are hydroelectric machines that are used to harness the hydro potential of a water resource. 

The hydro-power turbines are designed to convert the kinetic energy of flowing water into mechanical energy (which is subsequently converted to electrical energy by a hydropower generator). Here, we can make a distinction between hydro turbines and hydropower plants (which include hydroelectric power plants).

The hydropower turbine is shaped like a conventional water wheel having an axle and a series of blades. These are generally designed in such a way that they can be set up on hydro sites, which have high volumes of rapid flow rate as well as the head (the vertical distance from the hydro site to the hydro turbine). 

Hydro turbines function best when there is a fast-moving stream of water available. The amount of electricity generated by hydro turbines depends on the volume & speed of flowing water.

Different Hydroelectric Turbine Types

Here are some of the most common types of hydro turbines:

1. Francis Turbine
2. Kaplan Turbine
3. Pelton Turbine
4. Propeller Turbine 
5. Axial-flow Turbine
6. Cross-flow turbine

We shall be going through these hydro turbine types in detail, so as to understand the main differences among them.

Francis Turbine

Also known as the hydro-wheel, Francis hydro turbines are one of the earliest forms of hydro turbines that have been invented and used. They were first installed for hydroelectric power generation purposes in France back in 1849. Sir Francis Fox was a British engineer who is considered to be the inventor of this hydro turbine type.

Being simple and easy to maintain, this hydro turbine has gained much popularity especially when it comes to small-scale hydroelectric generators below 30 MW. It functions at an efficiency level of 41 %.

Kaplan Turbine

Kaplan or Kaplan-styled turbines are quite similar to Francis hydro turbines. They have been developed mainly by the American hydro engineer, Kaplan.

 Initially, it was believed that this hydro turbine type would be more suited for hydroelectric plant applications than Francis hydro turbines.

 However, recent research and studies suggest that there is hardly any difference in their performance when applied to hydroelectric power generation systems.

Kaplan hydro turbines are on average easier to install as compared to Francis hydro turbines due to its lesser weight and streamlined shape.

Pelton Turbine

Another popular hydro turbine discovered by Lester Pelton C. Pelton has a simple design with a single nozzle that allows water to fall vertically onto buckets attached around the rotor shaft. The rotation of these buckets pushes out the surrounding water through the nozzles. Pelton Hydro turbines were initially designed and patented in 1878.

Propeller Turbine

Also referred to as the propeller-type hydro turbine, they are hydro turbines that utilize the same technology as a ship’s propeller system. 

They use a similar proven hydraulic design where water flowing through a nozzle is accelerated by pressure towards a paddle wheel. 

Propeller hydro turbines can generate electricity at high-efficiency levels and are commercially used for hydroelectric power plants of large capacities above 100MW.

Unlike other hydro turbine types discussed above, Propeller hydro turbines have numerous drawbacks such as high maintenance cost due to its low technological simplicity without any guide vanes or control blades. It also has lower capacity factors compared to Francis hydro turbines.

Propeller Turbine:

This is another type of hydropower turbine. It features a runner and blades which will provide points of contact with the water. The main difference between propeller hydro turbines and Francis hydro turbines is that the latter uses older technology.

 The latter can be used for different applications such as hydroelectric power plants or even pumping stations where you need to have a high head but a low flow of water.

The Propeller type of hydropower turbines are well suited for high head and low flow rate sites since these turbines exhibit efficient performance at higher heads.

 Unlike Francis hydro turbines, there is no need for guide vanes or control blades with propellers, which makes it convenient in its installation purpose but not so good when it comes to maintenance.

Axial-Flow Turbine

This hydro turbine is similar to hydro turbines of the propeller type. It has two stages where water can fall onto a runner from the first stage as well as get accelerated to higher velocity. 

Then, it will be released to flow downwards through the second stage and produce energy in this manner. The main difference between axial hydro turbines and hydro turbines of the propeller type is that they use cylinders instead of buckets. 

Axial hydro turbines are known for their high-efficiency levels and require less maintenance compared to other hydro turbine types.

Cross-flow turbine

This hydro turbine utilizes the same technology as an axial hydro turbine but it is just smaller in size. The design of a cross-flow hydro turbine generates power at high efficiency levels which makes them the best hydro turbines for small hydro plants and hydroelectric generating systems. 

Unlike other hydro turbines, Cross-flow hydro turbines have practically no maintenance cost since they are relatively new in the market without any problems whatsoever with regard to their working mechanism or design.

Conclusion

Hydropower hydro turbines are categorized by their working mechanism into turbine types such as Pelton hydro turbines, Francis hydro turbines, Propeller hydro turbines and Axial-flow hydro turbines. 

Analyze and compare these hydro turbine types based on their characteristics, working mechanism, and performance. You can then proceed to choose the most suitable type of hydro turbine. After that, contact a reliable hydro turbine manufacturer for the best turbines.