Solar Energy
Why don't we get our energy straight from the source?
The Sun produces far more energy than humans can use. The Sun is also
the source of most of the energy we use. Fossil fuels and wind energy, for
example, originate with the Sun. So why don't we get all our energy from
the Sun? For one reason, it's not always practical.
Solar Energy
Solar energy is clean and renewable. Earth receives many times more
solar energy than humans could ever imagine using.
Energy from the Sun
The Sun is Earth’s main source of energy. The Sun gives us both light
and heat. The Sun changes hydrogen into helium through nuclear fusion.
This releases huge amounts of energy. The energy travels to Earth mostly
as visible light. The energy is carried through the empty space
by radiation. We can use sunlight as an energy resource, called solar
energy.
Solar Energy as a Resource
Solar energy has been used on a small scale for hundreds of years. Today
we are using solar energy for more of our power demands. Solar power
plants are being built in many locations around the world. In the United
States, the southwestern deserts are well suited for solar plants.
Solar Power Plants
Sunlight is turned into electricity at a solar power plant. A large group of
mirrors focuses sunlight on one place. This place is called a receiver
(Figure below). At the receiver, a liquid such as oil or water is heated to a
high temperature. The liquid transfers its heat by conduction. In
conduction, energy moves between two objects that are in contact. The
warmer object transfers heat to the cooler object. At a solar power plant,
the energy conducted by the heated liquid is used to make electricity.
Solar Energy Use
Solar energy is used to heat homes and water, and to make electricity.
Scientists and engineers have many ways to get energy from the Sun
(Figure above). One is by using solar cells. Solar cells are devices that turn
sunlight directly into electricity. Lots of solar cells make up an individual
solar panel. You may have seen solar panels on roof tops. The Sun’s heat
can also be trapped in your home by using south facing windows and
good insulation.
Consequences of Solar Energy Use
Solar energy has many benefits. It does not produce any pollution, and
there is plenty of it available—much more than we could possibly use.
But solar energy has problems. The Sun doesn't shine at night. A special
battery is needed to store extra energy during the day for use at night. The
technology for most uses of solar energy is still expensive. Until solar
technology becomes more affordable, most people will prefer to get their
energy from other sources.
Click the link to watch the video:
https://www.youtube.com/watch?v=m74bMrxhBkw
Summary
• Solar energy is the result of nuclear fusion in our nearest star.
• A liquid is heated and moves that energy by conduction.
• Solar power is expensive, but as demand increases, technology
improves and costs decrease.
Review
1. How is solar power collected on a large scale?
2. What are some of the disadvantages of depending on solar energy?
3. What are some of the advantages of using solar energy?
Here are the top questions that students are asking for this concept:
4. How does a solar cell convert light energy into electrical energy?
5. Can solar panels store energy?
6. Does a solar cell system generate energy?
7. How does a power tower concentrate solar energy?
8. How can solar energy be used to generate electricity?
