Over the period 2002 to 2007, the cost of energy rose steadily, as did the revenues generated by those companies in the business of extracting (in the case of fossil fuels), processing, moving, storing, and selling energy. For that reason, it is surprising to see that hydroelectric power generation in the United States actually saw a decline in revenues, as well as employment over the period. In 2002 the hydroelectric power generation industry employed 6,360 people and in 2007 it employed only 3,795.

Geographic reference: United States
Year: 2002 and 2007
Market size: $2.73 billion and $2.24 billion respectively
Source: “2007 Economic Census: Sector 22: Utilities: Preliminary Comparative Statistics for the United States 2007 and 2002,” July 31, 2009, available online here.
Original source: U.S. Bureau of the Census