grp 4 ppt on solar energy

2.  yellow dwarf star in the center of the solar
system
 diameter = 1,392,000 km, 109 times of earth’s
 mass = 2×1030kg, 330,000 times of earth’s
 99.86% of the solar system’s total mass
 ¾ hydrogen, the rest is mostly helium
 primary source of energy in the earth

3.  the earth receives 174 petawatts [1015 watts]
from the sun
 30% is reflected into space and the rest is
absorbed by land, oceans, clouds etc.
 the total energy absorbed by earth’s
atmosphere, oceans, land mass is 3,850,000
exajoules [1018 joules] per year
 energy entering the earth from the sun is
twice the energy harnessed from all non-
renewable sources of energy combined

4.  generating electrical power by converting
solar radiation into dc electricity using
semiconductors that exhibit the photovoltaic
effect
 The photovoltaic effect is the creation
of voltage or electric current in a material
upon exposure to light
 first observed by Alexandre-Edmond
Becquerel in 1839

5.  also called solar cell, is an electrical device
that converts the energy of light directly into
electricity by the photovoltaic effect
 made of monocrystalline silicon or
polycrystalline silicon or amorphous silicon
or cadmium telluride, or copper indium
selenide/sulfide
 first built by Charles Fritts in1883 by coating
the semiconductor selenium with an
extremely thin layer of gold

7.  photons in sunlight hit the solar panel and
are absorbed by semiconducting materials,
such as silicon
 electrons are knocked loose from their
atoms, and current starts flowing through the
material and this electricity is captured
 an array of solar cells converts solar energy
into a usable amount of direct current [DC]
electricity

8. “nellis solar power plant” contains 70,000 solar
panels that will generate 25 million kilowatt-hours

9.  “solar one”, california 1,800 sun-tracking mirrors
reflect heat to a central collector

10.  a solar farm in the philippines…

11.  pisay

12.  solar energy is a renewable source of energy
 in the presence of solar power, use of non-
renewable sources of energy like petroleum
can be lessened which also lessens pollution
 unlike others, solar energy can be harnessed
and used in remote locations like mountains
 even though solar panels are expensive, the
total amount that would be saved makes the
price of the panels will seem small

13.  solar panels are expensive
 solar power is inefficient in cloudy areas
 batteries and solar panels occupy more
space
 solar power maintenance is a problem
especially to those who doesn’t know the
proper technician
 disposal is difficult for the batteries and solar
panels when they have broken down
because they contain toxic chemicals like

14.  http://www.solarenergy-solarpower.com
 http://www.wikipedia.org [wikipedia]
 http://www.google.com [google images]
 the world of science, vol 10, technology of
change