Coal

= **Energy Source: Coal** = = = toc

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What is it?
media type="file" key="c1.mp3" Coal is a hard, blackish rock found underground. Coal is a **fossil fuel** -- something that formed over millions of years from the remains of dead plants and animals. As the dead plants were buried underground, the energy stored in them was buried, too. And how do plants get their energy? That’s right, from sunlight! So if you think about it, the energy we get from coal can actually be followed all the way back to the sun.

Fossil fuels are **non-renewable resources** because it takes so long to replace them. Right now, our society is using fossil fuels much quicker than they can be replaced in nature. Some people say that we should stop using coal so much so that there is some left for the people of the future, but others say that we should use what we have now and learn to use new kinds of energy only when we really have to. What do you think?

How does it work?
media type="file" key="c2.mp3" Coal forms in layers underground. The layers near the surface are easier to get to, but the layers underground produce a lot more energy. There are two different kinds of mining used to get coal. **Surface mining** is when miners use big machines to remove the coal that is close to the surface of the earth.

Surface mining is cheaper than **underground mining**, when miners must build deep elevator shafts and tunnels down in the earth’s surface. Surface mining is also safer than underground mining, because of the dangers the miners face going so deep underground. After the coal comes out of the ground, it is taken to a plant to be cleaned. Then it is shipped (usually by train) to be sold.

How is it used today?
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Most of the coal used in the U.S. is used to produce **electricity**. Actually, almost half of the electricity produced in the United States comes from coal. When coal is burned, it produces steam. The steam turns giant **turbines**, and the motion of the turbines creates electricity.

Coal is also used to make steel. When coal burns hot enough, it turns into a substance called **coke**. When the coke is mixed with iron ore, it produces the strong, flexible substance we know as steel.

What are the advantages?
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Humans have been mining coal for energy since the 1700s and we have gotten to be pretty good at it. What are some advantages to using coal? Well, there is a LOT of coal in the U.S., which makes it pretty cheap to use. Another advantage is that when you burn coal, it gets very, very hot, so a little bit of coal can produce a LOT of heat energy.

What are the disadvantages?
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When humans first started mining coal, we were very careless about it. When coal is burned, it produces harmful gases and chemicals. These harmful substances have been linked to global warming and water pollution. Now that we know more about the effects of burning coal, we are taking steps to make the process more environmentally friendly, but it still isn’t perfect. Also, at the rate we use coal today, we will run out of coal in just over 200 years. What will we do then?

Is there a solution for using coal energy in the future?
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What do you think? Should we keep using coal the way we do today? Should we stop using it altogether? Or is there another solution out there?

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©2008 E. Crispino