Solar power is the
harnessing of energy from the Sun for human application. Energy is generated
either by a solar thermal process of heating or through the photovoltaic
process. Several different technologies exist with designs ranging from small
low voltage installations for powering something as small as a traffic light,
to large scale solar farms intended to provide electricity for entire cities.
The technologies are typically categorized as passive or active, depending on
their methods of capture, conversion, and distribution.
Passive Solar Energy
Passive
solar energy uses direct sunlight without the aid of any other energy.
Typically passive systems are used for heating. Orienting a room to receive
maximum sunlight during the winter time is an example of passive solar energy.
Passive solar energy is also harnessed by simple devices, such as solar ovens
that simply collect heat energy from the sun to cook food.
Active Solar Energy
Active
systems require energy besides the Sun to function. Many solar energy systems
require fans or pumps for moving water or air. Some use energy to position
panels automatically throughout the day for maximum solar exposure. It is often
the case that active solar thermal systems employing pumps or fans have higher
solar savings fractions. Because of this, many people have considered the
possibility of a solar grid system in which active solar installations could
get their initial energy from an already solar fed grid.
Solar Thermal
Solar
thermal generates heat by collecting heat energy directly from the Sun. This
method is especially effective for water and space heating. Solar collectors
use heat energy from the sun to heat water or air. Water can then be stored in
hot water tanks for use, and warm air can be circulated throughout a building
for space heating. Active solar thermal systems often use fans or pumps to
circulate air and water but passive ones exist as well. Some passive systems
simply heat air by designing a room for Sun exposure or by using plumbing
techniques to create energy-free water pressure.
Photovoltaic
The
method of converting the sun's energy into electricity is known as the
photovoltaic process. Silicon-based materials known as solar cells collect the
Sun's light, rather than its heat, to create DC current. An inverter then
converts the DC current into standard AC current. Because of the conversion
some energy is lost. However, AC current is required for powering all household
appliances and, in some cases, communities offer incentives for feeding excess
energy back into the main grid.
Direct and Indirect Solar Energy
Direct
solar energy requires one step for converting the suns energy into useable
energy like heat or electricity. All of the aforementioned processes are
examples of direct solar energy. Indirect solar energy refers to multifaceted
collection processes such as turbines harnessing solar caused winds and
creating bio-fuel from plants which derive their own energy through photosynthesis.
Algae could prove to be an excellent source for this in the near future.
