Resource: Pennsylvania Energy: Energy from the Sun

Print Background Essay

Solar energy can be captured and transformed for use in our everyday lives and homes. It's not just a modern idea. In ancient times Romans would cover the windows in their homes with glass or mica in order to trap the heat from the sun during the cold winter months.[1] From the mid 1800s through the 1980s scientists concerned about depleting the earth's fossil fuels worked to invent and produce efficient ways of producing solar power.

Currently solar power is used in calculators, satellites, emergency road signs, and parking lot lights. Where the cost of stringing a conventional power line is high (such as for temporary road signs), solar can be a very cost-effective solution. Some homes even have solar panels as a means of producing some of their electricity.

Like homes with solar panels, the school and prison featured in this video cut the cost of electricity for themselves and the environment (e.g., with respect to their contributions to global warming). Why aren't we using solar energy more extensively?

Although research has improved the efficiency and cost of solar power in recent years, solar power is still less efficient than power from fossil fuels.

Due to the Earth’s natural tilt on its axis, the amount of direct sunlight that geographical locations receive varies with latitude. Locations near the equator are positioned at nearly ninety degree angles in reference to the sun, whereas locations at higher latitudes are positioned at much greater angles and receive far less direct sunlight. Therefore, the amount of solar energy that can be harnessed varies.

The amount of solar energy also varies with the time of year. For example, in Europe during the summer months, the northern hemisphere is tilted toward the sun, and therefore, the sun traverses a high, nearly vertical arch through the sky.[2] As the Earth continues its revolution and the northern hemisphere tilts away from the sun, Europe experiences winter. During these months, the sun travels a flatter, more southerly path.

[1] Smith, C. (1995). History of Solar Energy: Revisiting Solar Power’s Past. Technology Review, 98(5), 38-47.

[2] Hug, Rolf. The Solarserver: Forum for Solar Energy. Retrieved August 19, 2008 from http://www.solarserver.de/solarmagazin/anlageapril2000-e.html

Print Questions for Discussion

• You can use the University of Oregon’s Solar Radiation Monitoring Laboratory's “Sun Chart” program: http://solardat.uoregon.edu/SunChartProgram.html to chart a sun path chart for your town/school. Create and print or save a chart for your school. You need to know your zip code or longitude and latitude, and what time zone you are in. Then create and print or save a chart for a school far north of you and one far south of you. Compare the charts to see when the sun is at its peak in different places.
• Given that all schools installed exactly the same solar panels, discuss places in the world where schools with solar panels would collect more or less energy than ones you install at your school.
• What months will give your school the greatest energy from the sun? Pick a place in the world that is the same distance from the equator as your school, but in the opposite direction, and decide what months would give that place the greatest energy from the sun.
• To implement the use of solar energy using current technology, you will need to make some adjustments to your daily routines and try to live a less energy- intensive lifestyle. What energy intensive devices would you be willing to give up? What devices do you consider essential?