Environmental Engineering Reference
In-Depth Information
Table 2.2
Relationships among transmission voltage and construction cost
Transmission
voltage
Cost per unit of
capacity ($/MW-Mile)
Cost per mile ($)
Capacity (MW)
230
$2.077 million
500
$5,460
345
$2.539 million
967
$2,850
500
$4.328 million
2,040
$1,450
765
$6.579 million
5,000
$1,320
Source:
Green Power Superhighways, American Wind Energy Association/Solar
Energy Industries Association (2009)
cut peak load losses by 10 gigawatts. New high-voltage transmission
lines for renewable energy sources could be to energy what President
Eisenhower's interstate highway system was to transportation.
While conventional power plants can be constructed close to where
their electricity is needed, renewable energy sources are commonly not
near population sources, and the power must be transmitted long dis-
tances. For example, solar power is most effi ciently generated in south-
western United States, but the power may be needed in Chicago, 1,500
miles away. To solve this problem, supporters of renewables favor
construction of a new generation of high-voltage direct current (DC)
supergrids linking regions rich in wind, solar, or other renewable energy
sources with populated areas thousands of miles away. Over distances
greater than 600 miles, alternating current (AC) transmission lines
become increasingly ineffi cient, losing more than 10 percent of the energy
pumped into them, and they become more expensive than DC, whereas
a high-voltage DC line would lose less than 3 percent. Conversion of DC
to the AC that consumers need adds only an extra 0.6 percent loss.
33
The greatest challenge facing electric distribution with the existing
grid is responding to rapidly changing customer needs for electricity.
Increased use of information technologies, computers, and consumer
electronics has lowered the tolerance for outages, fl uctuations in voltages
and frequency levels, and other quality disturbances.
Crumbling Highways
The 4 million miles of roads in the United States range in quality from
one-lane loose gravel to six-lane asphalted interstate highways. Paved
roads cover about 60,000 square miles, about 2 percent of the nation's
