Introduction to Solar Energy An overview of the technologies and applications Modified by Georgia Agricultural Education Curriculum Office June 2002

On July 4, 1997, the Pathfinder spacecraft bounced to a stop on Mars On July 4, 1997, the Pathfinder spacecraft bounced to a stop on Mars. The next day, the rover Sojourner rolled out of one of the lander petals onto the surface of the planet to begin its mission of exploration.

Sojourner was able to move around the planet and examine rocks like this one named “Yogi” – located 20 feet from the Pathfinder lander – thanks to the power generated by the solar panel on its back.

Dramatic as this was, it was just one use of solar energy. To many students, exciting projects like this are what solar energy is all about. But there really is much more to solar energy technologies, how they are being used, and how they impact our lives today. This presentation will introduce you to the entire field of solar energy.

Let’s begin our overview of solar energy by asking: What do you see here? Take a close look – is this the profile of a beautiful young lady, or the face of an ugly, old woman? They’re both here, but for a variety of reasons that make up your own individual psychological make-up, some of you see one woman, some the other.

When people think of solar energy, the same thing often happens When people think of solar energy, the same thing often happens. Some see it as something for the future, others see it as something that is here today.

If you think solar energy is something to be used in the future . . . you may be picturing something like this solar array used by the space shuttle to provide for power needs in outer space. There are people who think that solar energy is something not quite down-to-earth and not ready to use today.

However, there are other people who think of solar energy as something that’s been around for a long time. Solar collector for heating water A home in California in 1906

For hundreds of years, people have wanted to harness the sun’s power for weapons, heating, and many other uses to make their lives more comfortable.

Actually, the first solar water heating collector appears to have been built in the 18th Century by a Swiss scientist who constructed a simple wooden box with a glass top and a black base. It trapped solar energy, and the collector reached a temperature of 190 degrees Fahrenheit.

So which view of solar energy -- for the future or for today – is correct? Probably a little of both. Solar energy will certainly play an important role in the future energy needs of our planet, but it’s also here today and ready for hundreds of uses in homes, businesses, and industry.

The sun is an inexhaustible power supply The sun is an inexhaustible power supply. It brings enough energy to our planet every single day to meet a full year’s worth of energy for everyone on Earth. And during the past century – back to 1891, in fact, when the first solar collector was manufactured in the United States, U.S. industry has developed a variety of products that have proven both reliable and cost-effective in meeting all kinds of energy needs.

The batteries in this solar-powered light in a remote part of Key West, Florida, are charged by the sun during the day to provide power for street lighting at night.

But to many people, solar power today means just reliable calculators, watches and other simple home products like this lantern that use solar power instead of electricity to charge the batteries.

They don’t realize that millions of people around the world use solar energy because it is the only available, reliable power source for many of their basic needs such as lighting and water pumping.

Meanwhile, do-it-yourselfers have long tried to build their own solar systems to take advantage of the free power provided by the sun . . .

The owner of a small laundry in northern Florida tried to build his own concentrating system for water heating. (We don’t know if the sign in the background was put up before or after this homemade system was built.)

But we do know that growing public concern about environmental problems . . .

including global warming, acid rain and toxic air emissions, has in recent years turned a great deal of attention to environmentally friendly solar energy systems.

The nonrenewable sources we use today – including coal, oil, kerosene, diesel, propane and natural gas – are all limited in availability, and are also partly to blame

Meanwhile, there is one energy source that is free and inexhaustible Meanwhile, there is one energy source that is free and inexhaustible. It’s like a giant nuclear reactor – only this one is located 93 million miles away.

It’s not uncommon around the world to see solar systems used along with the traditional ways of life to become an integral part of people’s lives.

The house of the future? This zero-energy house in the Netherlands has 30m2 of PV panels for power generation and 12m2 of solar collectors for water and space heating.

No matter what the future will be like, one thing is for certain: some type of energy will be needed to power it.

What will that energy source be? The answer ought to be obvious. It’s been up there all the time.

Discussion Questions Why do you think solar energy is not used more today? Do you think governments should adopt measures to use more solar energy in the future, or rely on fossil fuels as long as they are available? What are some of the economic, social, and environmental issues involved in the use of solar energy?