Environmental Engineering Reference
In-Depth Information
Biofuels appear to have a bright future for cars and trucks in the United
States if naturally occurring nonfood plants are brought online as
feedstocks.
Bioelectricity
Recent research has added a new twist to the biofuels debate. Convert-
ing biomass to electricity for charging electric vehicles may be a more
climate-friendly transportation option than using biomass to produce
ethanol fuel.
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An acre of switchgrass, for example, would allow vehicles
to travel 81 percent farther on average if it were pressed into pellets and
burned to generate electricity than if it were converted to liquid fuel.
Converting switchgrass to electricity would also reduce greenhouse gases
by 108 percent more than if the feedstock were converted to ethanol.
Energy from Moving Water: Our Major Source of Electricity
Hydroelectricity is second to biofuels as a source of the nation's alterna-
tive energy, but it is the major renewable energy source for electric power
(table 7.2). Only 3 percent of the dams in the U.S. currently generate
electricity, so there is considerable room for expansion. Generating elec-
tricity using water has several advantages, primarily its low cost once
the dam is built. Plants are automated and have few personnel on site
during normal operation. In addition, because there is no fossil fuel use,
Table 7.2
Generation of hydroelectric power in the United States in 2008 (thousands of
megawatt-hours)
Washington
70,283
Oregon
30,747
New York
24,346
Idaho
9,055
Montana
8,858
Arizona
6,827
Tennessee
5,736
Alabama
5,371
Arkansas
4,362
Maine
3,551
North Carolina
3,039
TOTAL
172,175 = 71% of total generation
Source:
Energy Information Administration (2009).
