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Fig. 4: Computer simulation using solar radiation data shows how the output of two
photovoltaic power systems cold be added to the utility's generation to help meet
peak electric demand in the summer. The fixed-tilt array faces south and is tilted
from the horizontal at an angle equal to the site's latitude. The tracking array
uses motors and gear drives to point the array at the sun throughout the day.
Depending on location, the photovoltaic system with the 2-axis tracking array
receives annually 25% to 40% more global solar radiation than the fixed-tilt
photovoltaic system and provides more power for longer periods. This must be
weighed against the higher initial cost and maintenance required for the tracker.