More power to you

摘要

Suppose someone sends you two boxes, each full of a useful product. When you open the first box, it remains almost as full as when it was sent--only 10 percent of its contents are missing. The second box arrives on the same day but isn't nearly as full; in fact, 73 percent of the contents have disappeared in transit.In this example, the first box contains energy from natural gas captured at the well. By the time the natural gas has gone through a processing plant and traveled through underground pipes, 90 percent of the original energy is delivered to your home. In contrast, the second box contains electrical energy made from coal extracted from a mine or from natural gas. As the energy from coal or natural gas is converted into electricity at a power plant and then moves through overhead transmission lines, to the electric substation and through neighborhood power lines before delivery to your home, all but 27 percent of the energy is lost along the way.