Hydroelectric energy has several advantages and disadvantages. Some advantages of hydroelectric power plants compared to regular of fossil fuel power plants are that fuel is not burned in hydro plants, so there is no air pollution; the water used is renewable and free, so it can be replenished with nothing really being used. Those are the good things, but now for the few bad. Hydro plants have to have an existing waterfall or an area …showed first 75 words of 513 total…

…showed last 75 words of 513 total…the vertical distance from the top of the water to the bottom where it flows out. Flow is how much water is moving past a specific point. (ABS) The total amount of water power that can be extracted from the water all depends on the head and flow. The formula to calculate power is Power = (Head) * (Flow) divided by 10. This is one of the reasons the Hoover Dam or many other dams are so tall.