Hydroelectric Power
Hydroelectric power in the U.S was first introduced with the completion of the Hoover Dam in 1935.  Hydroelectricity is more efficient than coal electricity because there are fumes involved with burning the coal.  And, of course, there is no coal involved with the production of hydroelectric energy.  Even though the cost of building the dam is very high, in the long run it will cost less to create energy.  The reason this is, is because you have to dig coal from out the ground, and water flows in rivers, and streams, and lakes.  With that said, all you have to do is stop water flow, and build a dam-no mining involved.