ey work the same way as a wind turbine, but instead of turning because of wind, they turn because of the water current/tidal waves. This is why they are also sometimes known as tidal turbines.
Water turbines were designed because many people have complained about seeing wind turbines in their backyard, or even just near their homes. They believe that the mind mills are ugly, and inconvenient. This was one of the many reasons that scientists came up with the idea of water turbines.
The way the energy is made is when the sluice gates open at points when the tide is high enough. Once they let the water through the gates, it pushes into the Francis runner, and forces it to spin, which is the movement that creates energy.
This type of alternative energy can be used for any electronic item in our everyday lives. It is used by many people around the world, and although it is just starting to become a well-known source of alternative energy, it has made its big debut in 16 different locations around the world.
This energy type is able to be stored for later use, thanks to hydro-power facilities. You may also ask, is this type of energy renewable? The answer is yes, this type of energy is renewable. This is because water currents will always happen for as long as the Moon and the Sun continue to cause a gravitational pull. This is the force that cause ocean currents to occur. Although waves will always happen, due to global warming, they may not always be at a low enough sea level. In order for the water turbine to make energy, the tidal must be at a high sea level. Although it seems that there are many contingencies, about 70% of the earth's surface is covered in water, therefore, water turbines/tidal power could become one of the most used, and most easily renewable source of alternative energy once it is more recognized in the future.
A few of the positive aspects of water turbines are that, although they are a bit more expensive than wind turbines, they are still quite cheap to build. Another good thing about water turbines is that, people have complained about seeing large wind turbines in their backyard, so, this way, they don't have to see anything. Although, some of the negative aspects are, that this type of alternative energy is very new, so scientists do not know many of the side effects yet. What they do know is that it can sometimes disrupt large marine energy. One of the other side effects is, that varnish particles, which are in the turbine oils used by hydro-power facilities, are by-products of the oil used in the making of water turbines.
A few reasons that water turbines are a bit harder to build than wind turbines are: water is about 800 times denser than air/wind; it has to be much stronger and more stable. Because they must be built better(in order to stand), they are a bit more expensive than wind turbines. Besides reasons that make water turbines harder to build, there are some reasons to do with the environment that make them unsafe to build. One of these reasons are, that much of the time, fish get stuck inside the generator/turbine, while trying to swim through, and there have actually been many discoveries of dead fish near the generators of many water turbines.
Water turbines are not very popular, therefore there aren't many around the world, although there are a few. They are in France and another is being inserted in to Niagara Falls. Some more locations are: Hammerfest, Norway, Devon, England, East River;New York City, Orkney, Scotland. S, Korea, Brisbane, Australia, San Francisco Bay, Eastport, Maine, and Messina;Italy. There are going to be more installed, but because a very specific high tide level is required, it is a very new form of alternative energy, and because we don't know much about how it will affect the water currents&marine life, there are not many around.
Here is a graph representing the amount of energy that different types of water turbines generate: