Utilities Select Sector SPDR® ETF

The most important factor that affects electricity demand is household income. According to the U.S. Energy Information Administration (or EIA), between 1981 and 2001, household real disposable income increased by 49%—from $17,217 to $25,698.

The industry’s supply chain consists of three broad categories—generation, transmission, and distribution. Power generation requires a fuel source—for example, coal, nuclear, natural gas, or wind—and a power plant to convert the fuel source into electricity.

The top electric utility companies in the U.S. include Duke Energy, Exelon Corporation, Southern Company, NextEra Energy, and Dominion Resources. These companies are largest in terms of market cap.

Electricity comes from energy sources that are found in nature. These sources are called primary energy sources. They’re the first form of energy. Primary energy sources include coal, gas, oil, wind, and water.

As of December 31, 2013, CLNE served ~779 fleet customers operating ~35,240 natural gas vehicles—it also owns and operates 471 natural gas fueling stations.