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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, very few people take advantage of this energy to power their homes or offices.
One problem is cost. Solar equipment generates power at about the same price as the electric company. But installing solar panels and other gear can be complex, with costs starting at $10,000. Weather is another problem. Cloudy or snowy days produce less solar power.
Even so, many people want to use renewable energy sources such as solar. Unlike the Sun, oil and coal cause pollution. Worse still, we’ll run out of them one day.
How Solar Cells Work
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 collected and used solar radiation. The buildings faced south to draw maximum sunlight. 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. But there’s a big problem with wind power. Like the Sun, it’s unpredictable.
Solar power can be seen in a greenhouse. The glass lets in and traps some light, so plants can grow in any weather. Earth’s atmosphere works in a similar way. But burning oil and coal releases “greenhouse gases,” like carbon dioxide, into the air. These trap greater amounts of sunlight, making the Earth warmer. Some scientists believe this warming could melt polar ice sheets. It could also cause huge changes to our environment. ▼
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 consists of 24 satellites that orbit the Earth. They allow people with a GPS receiver to determine their exact longitude, latitude, and altitude. The Sun is an important part of the GPS. Those satellites are all powered by solar cells.
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 also can be harmful. Deadly skin cancer rates have skyrocketed in the last 30 years. That’s because more people are sunbathing and going to tanning salons. ▼
