Download Preview of Period 15: Uses of Solar Energy

Preview of Period 15: Uses of Solar Energy
15.1 Solar Insolation
What determines how much solar insolation
reaches various regions of the Earth?
15.2 The Greenhouse Effect
What is the Greenhouse Effect?
What changes can it make to the Earth’s
environment?
15.3 Using Solar Energy
What is the efficiency of a solar cell?
How can solar energy be used in buildings and
homes?
14-1
Solar Insolation
Solar insolation is the amount of solar power
passing through a given area.
The amount of solar insolation on a region of
the Earth depends on
♦ the season of the year. Due to the tilt of
the Earth’s axis, the northern hemisphere
receives more insolation during the summer.
♦ the latitude. Higher latitudes near the poles
receive less insolation and the equator receives
more.
♦ the alititude above sea level. Higher elevations
received more
♦ the amount of cloud cover and pollution in the
atmosphere that reflect and absorb radiation
from the Sun.
14-2
The Solar Power from a Solar Cell
The power from a solar cell depends on
• the amount of solar insolation striking
the cell
• the size (area) of the cell
• the efficiency of the solar cell
P = I x A x Eff
where
P = power (in watts)
I = solar insolation falling on the Earth (
in watts/meter2)
A = area of collector (in meters2)
Eff = the efficiency of the solar cell
Nuclear Energy
Nuclear energy is released during nuclear
fusion reactions when individual nucleons fuse
into helium nuclei and during fission occurs when
atomic nuclei break apart.
Nuclear Fusion
♦ In the Sun’s core, protons and neutrons fuse
into atoms of Helium
♦ During fusion, photons of electromagnetic
energy are given off.
♦ The photons travel to the surface of the Sun
and are radiated into space.
♦ A very high activation energy is needed for
o
nuclear fusion – the Sun’s core is 16,000,000 C.
o
(The surface of the Sun is 6,000 C)
Non-Solar Energy Sources
Tidal energy
♦ Two high tides per day can be used to
generate electricity
♦ Energy source: gravitational attraction
between the moon and the Earth
Nuclear Energy
♦ Fission reactions (radioactive atoms decay
giving off energy)
♦ This thermal energy can be used to generate
electricity by heating water to produce
steam, which turns turbines in a generating
plant.
♦ Energy source: uranium ore, which originated
in the Earth’s formation
Geothermal Energy
♦ The interior of the Earth (molten rock)
contains thermal energy. Some energy is
released by volcanoes, geysers, and hot
springs.
♦ This thermal energy can be tapped to
generate electricity and heat buildings.
Tidal energy
♦ Two high tides per day can be used to
generate electricity
♦ Energy source: gravitational attraction
between the moon and the Earth
♦ Tidal energy comes from the gravitational
interactions between the Earth, moonand
Sun.
♦ This gravity causes the oceans to form two
bulges, one on either side of the Earth.
♦ As the Earth spins on its axis, land bordering
the oceans passes through both bulges each
day causing tides.
♦ Tide water flowing into a harbor can be used
to turn electric generator turbines.
Fuel
Fossil
Biomass
Wind
Tidal
Hydroelectric
Nuclear
Geothermal
Solar
Advantages
Disadvantages