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Solar Energy Disadvantages

• Uses large amounts of fuel to build

• Large amounts of land used

• Bird mortality – higher than wind power

• High capital cost

• Toxic chemicals used

• Displacement of local animals

• Visual blight

Solar Energy Systems

Solar energy systems use solar radiation for heating buildings and water; for producing

high temperature steam for industrial process heat and to generate electricity; or to

convert solar energy directly into electricity. The total amount of energy supplied by

these systems in 1999 is estimated by the EIA at 0.07 quads. The actual amount is

difficult to determine because the exact number of working solar systems is unknown,

and the amount of solar radiation converted to useable energy varies at every installation.

Solar Thermal-Electric Power Plants Heat from solar energy is also used to produce

electricity. The Solar Electric Generating Systems (SEGS), located in the Mojave Desert

at Harper Lake and Kramer Junction, California, are the largest solar power plants in the

world. The SEGS consist of nine hybrid solar thermal parabolic trough/natural gas

turbine power plants. These power plants have a combined generation capacity of 354

MW (peak). The U.S Department of Energy (DoE) and 12 electric utilities retrofitted the

10 MW Solar One Power Tower, a solar thermal central receiver pilot plant near

Barstow, California. Solar One produced 35 billion kWh from 1984 to 1988. Solar Two

began full power production in early 1996, and completed its testing in 1999. The plant

has since stopped operation. While in operation, the plant generated 8.5 billion kWh. The

DoE has also supported the development of parabolic dish-Stirling engine systems up to

25 kilowatts capacity for utility and remote power applications.

Photovoltaic Systems Photovoltaic systems (PV) are based on solar electric cells, which

convert solar radiation directly to electricity. Individual solar cells are configured into

modules of varying electricity-producing capacity. Modules are rated on their peak

electricity generating in Watts (Wp) capacity at 1,000 watts per m2 (10.76 watts/ft 2) of

solar radiation. PV applications range from powering watches and calculators to large

installations with thousands of peak kilowatts generating capacity (KWp) for utility

power. The largest number of systems are installed where utility power line extension or

the use of fossil fuel generators are expensive or unfeasible, such as: remote

communication facilities; rural homes, farms and ranches; marine and railroad signaling

devices; and highway sign, billboard and parking lot lighting. The number of systems

connected to electricity distribution and transmission systems is increasing. These types

of systems range in size from systems of less than one to several kilowatts on houses, to

systems over 100 kilowatts on large buildings.

Shipments of PV modules have increased steadily since 1982, the first year that data was

collected. In 1982, a total of 6.99 MWp of generating capacity were shipped for

installation in the US. In 1999, shipments within the US totaled 21.225 MWp (about 4.8

MWp were imported). (About 55.5 MWp were exported.) This was a 31 percent increase

over shipments in 1998. Assuming that all of the PV modules that have been shipped in

the US since 1982 are "in the sun," then the total installed PV capacity in the US is at

about 151 MWp. Assuming that all of these systems are in operating order (however

unlikely), and an average daily solar insolation for the entire country of 4.5 kWh (per

square meter per day), then these systems could have potentially produced around 248

million kWh (of direct current electricity) in 1999. This would be sufficient to meet the

electricity demand of about 40,000 households in the US.