As time past, Rural Electrification became very vital when it came to the electricity of the cities and not the only that, but the power plants became more efficient as they converted many things including solar power into energy that would be given to the cities. Eventually in the 20th century, the power generators came. By power generators, this meant the coming of dams and the use of hydroelectricity. In this method, the amount of power and electricity relied on the force and the power of the water that came. In today's society, we have dams and reservoirs that hold the water supply and use it for electricity such as the Hoover Dam, generating many kilowatts. With the dams and reservoirs came the wind farms, which reduced the cost of wind-produced electricity.