Environmental Engineering Reference
In-Depth Information
TABLE 4.2
U.S. Energy Consumption by Energy Source (2008)
Energy Source
Energy Consumption (quadrillion Btu)
Total
99.438
Renewable
7.367
Biomass (total)
3.852
Biofuels
1.372
Waste
0.436
Wood and wood-derived fuels
2.044
Geothermal energy
0.360
Hydroelectric conventional
2.512
Solar thermal/PV energy
0.097
Wind energy
0.546
Source:
EIA,
U.S. Energy Consumption by Energy Source
, Environmental
Investigation Agency, Washington, D.C., 2007 (http://www.eia.doe.
gov/cneaf/solar.renewables/page/trends/table1.html).
The technology for using falling water to create hydroelectricity has existed for
more than a century. The evolution of the modern hydropower turbine began in
the mid-1700s when a French hydraulic and military engineer, Bernard Forest de
Belidor, wrote a four-volume work describing the use of a vertical-axis vs. horizon-
tal-axis machine. Water turbine development continued into the 1800s. A Brush-arc
light dynamo driven by a water turbine provided theater and storefront lighting in
Grand Rapids, Michigan, in 1880, and in 1881 a Brush dynamo connected to a tur-
bine in a flour mill provided street lighting at Niagara Falls, New York. These two
projects used direct-current (DC) technology.
Alternating current (AC) is used today. That breakthrough came when the elec-
tric generator was coupled to the turbine in 1882, which resulted in the world's first
hydroelectric plant, located on the Fox River in Appleton, Wisconsin. The Appleton
hydroelectric power plant is considered to be one of the major accomplishments of
the Gilded Age (1878-1889) (Library of Congress, 2009). People across the United
States soon enjoyed electricity in their homes, schools, and offices, where they were
able to read by electric lamp instead of candlelight or kerosene. Today, we take elec-
tricity for granted and cannot imagine life without it.
Table 4.2 shows the energy consumption by energy source for 2008; in that
year, hydropower power accounted for 2.512 quadrillion Btu. Ranging in size from
small systems (100 kW to 30 MW) for a home or village to large projects (capacity
greater than 30 MW) that produce electricity for utilities, hydropower plants are
of three types:
impoundment
,
diversion
, and
pumped storage
. Some hydropower
plants use dams, and some do not. Many dams were built for other purposes, and
the hydropower function was added later. The United States has about 80,000 dams,
of which only 2400 produce power. The other dams are for recreation, stock/farm
ponds, flood control, water supply, and irrigation. The types of hydropower plants
are described below.
