Environmental Engineering Reference
In-Depth Information
advanced designs are experimenting with molten nitrate salt because of its
superior heat-transfer and energy-storage capabilities. The energy-storage
capability, or thermal storage, allows the system to continue to dispatch
electricity during cloudy weather or at night.
Smaller CSP systems can be located directly where the power is needed. For
example a single, dish/engine system can produce 3 to 25 kilowatts of power and
is well suited for such distributed applications. Larger, utility-scale CSP applica-
tions provide hundreds of megawatts of electricity for the power grid. Both linear
concentrator and power tower systems can be easily integrated with thermal storage,
helping to generate electricity during cloudy periods or at night. Alternatively, these
systems can be combined with natural gas, and the resulting hybrid power plants can
provide high-value, dispatchable power throughout the day.
ENVIRONMENTAL IMPACTS OF SOLAR ENERGY
All energy-generating technologies, including solar technologies, affect the environ-
ment in many ways. Solar energy has some obvious advantages in that the source is
free; however, the initial investment in operating equipment is not. Solar energy is also
environmentally friendly, requires almost no maintenance, and reduces our depen-
dence on foreign energy supplies. Probably the greatest downside of solar energy use is
that in areas without direct sunlight during certain times of the year solar panels cannot
capture enough energy to provide heat for homes or offices. Geographically speaking,
the higher latitudes do not receive as much direct sunlight as tropical areas. Because of
the position of the sun in the sky, solar panels must be placed in sun-friendly locations
such as the U.S. desert southwest and the Sahara region of northern Africa.
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Most of the land used for larger utility-scale solar facilities, depending on their loca-
tion, can raise concerns about land degradation and habitat loss. This is the case even
if abandoned industrial, fallow agricultural, or former mining sites are used. Total
land area requirements vary depending on the technology, the topography of the site,
and the intensity of the solar resource. Estimates for utility-scale PV systems range
from 3.5 to 10 acres per megawatt, while estimates for CSP facilities are between 4
and 16.5 acres per megawatt (UCS, 2013). Unlike wind facilities, there is less oppor-
tunity for solar projects to share land with agricultural uses; however, land impacts
DID YOU KNOW?
Abandoned mine lands (AMLs) are those lands, waters, and surrounding
watersheds where extraction, beneficiation, or processing of ores and minerals
(excluding coal) has occurred. These lands also include areas where mining or
processing activity is temporarily inactive.
