2. Introduction
Solar energy is a source of energy that has been
used for thousands of years whether we know it or
not. Since the beginning of time, organisms have used
the sun to gain power. Humanity has since improved
and has found ways to employ solar energy into
useful products. This renewable source of energy is
being used in several products today. While it has
some negatives to it, the benefits far outweigh the
consequences. With the support of all of society, solar
energy has a great and limitless potential.
3. How Solar Energy Works
Today
• On a cloudless day, the energy from the sun on Earth’s surface is about 1,000 watts per square meter. Each square
meter collects about the same amount of energy as a barrel of oil.
• There are several ways that the energy from the sun can be used, including:
• Solar heat collectors. These contraptions not only gather, but also store solar energy. They are usually large, flat
boxes that are black on the inside and are covered with glass. Usually, pipes in these boxes carry a water-
alcohol mixture is used to heat water in a tank or it is passed onto radiators that heat the air.
• Solar thermal concentrating systems. These systems can produce temperatures up to 3,000 degrees Celsius. They
come in three designs, with the most common being the parabolic trough, which is a long and curved mirror-like
design that allows sunlight to be concentrated on a liquid located in a tube which runs parallel to the mirror.
Parabolic dish concentrators are similar, except they concentrate sunlight onto a single focal point. They can
produce much higher temperatures than parabolic troughs. The third type of design is called a central receiver.
It is a large field of mirrors which can concentrate sunlight on top of a high tower. The heat from the sun boils
water, producing steam. The steam then powers a generator.
• Photovaltics. These consist of two layers of a semiconductor material usually composed of silicon crystals. The
bottom layer is bonded with boron, which attaches to silicon to form a positive charge. The top layer bonds with
phosphorous, which bonds with the silicon to create a negative charge. Sunlight enters the cell, causing
electrons to come loose in both layers. The movement of these electrons produces energy.
4. The History of Solar Energy
• People have been using the sun as energy for thousands of years. Beginning in about the 7th Century B.C., cavemen would
use magnifying glasses to make fire for cooking food and keeping warm. About 4,000 years later, Romans and Greeks used
the sun to light torches. Since then, there have been several of discoveries relating to the use of the sun as energy and
power.
• Auguste Mouchout is credited with being the first to directly convert solar radiation into mechanical power in the late 1800s.
• John Ericsson invented the first solar-powered steam engine in 1870. He also invented the parabolic trough, which is a
reflector.
• Aubrey Eneas designed a motor that was similar to Mouchout’s except that it was 50 percent larger.
• Henry E. Willsie was the first to store the sun’s energy so solar power could be used when it was not bright outside.
• Frank Shuman created a machine similar to Willsie’s, but it performed very poorly at first. He had to figure out a way to raise
the pressure of the steam to run his machine efficiently. He then realized that instead, he could just figure out a way to run
the machine at a lower pressure. The engine was then a successs.
• Shuman’s remarkable machine was unfortunately destroyed during World War I.
• Sun Power Co. created an engine that combined Ericsson, Willsie, Mouchout, Eneas, and Shuman’s ideas together.
• The first commercial use of solar energy was when solar power was used to assist with space exploration.
• Luz Co., the producer of over 95% of the world’s solar-power electricity, filed for bankruptcy in 1991.
• The U.S. Government began embracing solar energy in 1977 when they created the Solar Energy Research Institute.
• Several people did not take well to solar energy because it is a highly expensive and very risky alternative to fossil fuels.
5. The Future of Solar Energy
• Technology is improving daily with solar energy.
• The most advanced solar cells are currently being produced,
and they will continue to improve.
• The public is becoming more and more aware of the benefits.
• People are looking for alternatives because they are starting to
realize that fossil fuels will eventually run out.
• There is more support for solar energy now than there ever has
been.
• With more funds due to the support of the public as a whole,
solar energy has remarkable potential.
6. Pros and Cons
Pros
• Will never run out
• Widely available
• No noise pollution
• Support from government
• Low maintenance
• Reduces costs of electricity
• Environmentally friendly
• Improving technology
• Abundant
• Can be used for many things
Cons
• Expensive
• Requires a lot of space
• Storage is expensive
• Access is limited at certain times
(sun doesn’t shine all the time)
• Materials for use sometimes hard
to find (such as to make solar
cells)
8. Evaluation of Project
This project really opened my eyes to several things
that I did not know about solar energy. I now know how it
works, which I was unsure of before. I also am aware of
several products that employ the use of solar energy. I know
that it has been used for thousands of years, but it really
gained support in the late 1800s-early 1900s. I’ve realized
that the benefits are greater than the disadvantages and that
solar energy should definitely be used more widely than it is
today. If it is, the world will be a much more
environmentally friendly and cleaner place.
