A dam as a source for hydropower: an explanation
One of the best ways to generate electricity is with a hydroelectric dam. The main reason for this is that hydropower does not release any emissions into the atmosphere. It does however require that a dam be built in most cases. This will create a reservoir that can be used for a variety of purposes. That being said most dams are located too far from anything to be used for anything but electricity generation.
A lot of people are confused as to why it is necessary to build a dam when you are building a hydroelectric plant. After all the flow of the river should be able to turn the turbines to create power. The reason that a dam in necessary is to increase the amount of water that is available to spin the turbines and to make sure that there is always enough water. This may not be the case if you are relying on the river itself. The water levels and speed at which the river flows could change so a dam is a much more reliable option.
The basic ideas behind using a dam as a source of hydropower is to build up a reservoir of water and then allow the water to flow to a lower level on the other side. This will allow the water to flow at a controlled rate so that it can spin the turbine. In most cases the water will run through a tunnel that goes through the dam in order to get to the turbines. On large dams the elevation change can be huge, which will be very obvious when you see the dam.
In most cases when dams are being built to generate hydroelectricity they are very large. This is mostly because it is more economical to build one large dam than several small ones. That being said in a lot of cases one facility will often have several different dams built right next to each other. This will allow the water to turn more than one turbine before it returns to the river. It also makes it easier to build the dam and to control the level of water in the reservoir.
While dams are widely used as a source of hydropower they are becoming less and less common. It is hard to get approval for dams these days because of the reservoir that it creates. The reservoir will cause the loss of habitat for the wildlife in the area and in some cases may also require people to be relocated. Because of this a lot of the new hydro plants that are being built are relying strictly on the flow of the river. At least that is the case in the developed world, in other places several very large hydro dams are currently under construction.