Count to 60. By the time you’re done, Earth will have soaked up enough sunlight to meet the world’s energy needs for an entire year!
Unfortunately, few people take advantage of this incredible energy source to power their homes or offices.
One problem is cost. Although solar equipment generates power at about the same price as the electric company, installing solar panels and other gear can be complex and expensive, with costs starting at $10,000. Weather is another problem. Cloudy or snowy days make it hard to generate electricity.
Nevertheless, many consumers want clean energy from a renewable source. Unlike the Sun, energy sources such as oil and coal cause pollution and will one day give out.

As the Sun rises, the solar cells produce more power and the batteries produce less.
Solar-powered homes are not new. Around A.D. 1100, in what is now New Mexico, the Anasazi people built dwellings that were perfect for collecting and using solar radiation. The buildings faced south to draw maximum sunlight. Their thick stone and adobe walls absorbed heat during the day and released it at night. ▶


◀ When the Sun’s energy reaches the lower atmosphere, about 0.25 percent of it gets turned into wind. By the middle of this century, wind could satisfy 10 to 20 percent of the world’s demand for electrical energy. One of the biggest problems with wind power is that, like the Sun, it’s unpredictable.
Solar power can be seen in a greenhouse. The glass lets in and traps some light, so plants are able to grow in any weather. Earth’s atmosphere works in a similar way. Unfortunately, people are releasing more “greenhouse gases,” like carbon dioxide, into the air by burning oil and coal. These trap greater amounts of sunlight, making the Earth warmer. Some scientists believe that global warming could melt polar ice sheets and cause radical environmental changes. ▼

Check It Out!
Which state calls itself “the Sunshine State”?
Florida, but South Dakota was long known as the Sunshine State.


▲ For sailors, the Sun and other stars were once the only way to tell east from west or north from south. Today, the Global Positioning System (GPS) is taking over that job. The GPS is 24 Earth-orbiting satellites that allow people with a GPS receiver to determine their precise longitude, latitude, and altitude. The Sun is an important part of GPS, because the satellites that pinpoint locations are all solar-powered.
Too little sunlight can be bad for your health. In far northern countries, winter days are short and depression can set in. To combat it, some people get artificial sunlight. Too much sun can be harmful as well. Deadly skin cancer rates have skyrocketed in the last 30 years as more people sunbathe and go to tanning salons. ▼
