Electricity generation facts for kids
Electricity generation is all about making electricity so people can use it. Most of the electricity we use is made by giant spinning machines called electrical generators. These generators are turned by different kinds of engines.
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How We Started Making Electricity
Making electricity in one big place became really helpful when we figured out how to send it to many homes and businesses. This was possible thanks to special devices called power transformers. Transformers can change the strength, or voltage, of electricity. This meant electricity could travel long distances cheaply through power lines as alternating current.
People started using electric light bulbs, electric motors, and many other electric items in the late 1800s. To power these, we began using different energy sources to run the generators. These sources include coal, nuclear power, natural gas, water power, and petroleum. A smaller amount of electricity also comes from solar energy, ocean tides, wind generators, and geothermal sources (heat from inside the Earth).
Why We Need So Much Electricity
The world needs a lot of electricity! There are two main ways to get enough power for everyone. The most common way is to build very large power plants that create and send out electricity. However, some of these big projects can cause problems for the environment. For example, they might create air or radiation pollution, or flood large areas of land.
Another way is called Distributed generation. This means making electricity on a smaller scale, closer to where people use it. These smaller power sources often create electricity as a side product of other activities. For instance, gas from landfills can be used to power turbines and make electricity.
Different Ways to Generate Electricity
How Turbines Make Power
Most of the electricity we use comes from spinning turbines connected to electrical generators. Turbines are spun by a moving fluid, which is usually steam, water, wind, or hot gases. This fluid acts like a messenger, carrying energy to the turbine.
Here are the main fluids used:
- Steam: Water is boiled to create steam. This can be done by nuclear fission (splitting atoms) or by burning fossil fuels like coal, natural gas, or petroleum. Some newer power plants use the sun's heat to boil water. Special mirrors called solar parabolic troughs and solar power towers focus sunlight to heat a liquid, which then makes steam.
- Water: Flowing water pushes the turbine blades. This happens at hydroelectric dams or from the movement of ocean tides.
- Wind: Most wind turbines use natural wind to generate electricity. There are also Solar updraft towers, which create their own wind inside a tall chimney by heating the air with sunlight.
- Hot Gases: Turbines can also be directly spun by hot gases made from burning natural gas or oil.
Some power plants use a clever method called Combined cycle. These plants use both steam and gas turbines. They burn natural gas in a gas turbine and then use the leftover heat to create more electricity from steam. This makes them very efficient, sometimes turning up to 60% of the fuel's energy into electricity.
Engines That Pump Power
Smaller electricity generators often use reciprocating engines. These engines burn diesel fuel, biogas, or natural gas. Diesel generators are often used for backup power, like when the main power goes out. Biogas, which comes from things like landfills or wastewater treatment plants, is often burned right where it's made to power these engines or small gas turbines called microturbines.
Solar Panels: Direct Sunlight to Electricity
Unlike solar heat concentrators that boil water, photovoltaic panels (solar panels) turn sunlight directly into electricity. Even though sunlight is free, solar panels can be expensive to make, and they only turn about 10-20% of the sunlight into electricity. For a long time, solar panels were mostly used in faraway places without access to the main power grid, or as an extra power source for homes.
However, solar panel technology has gotten much better and cheaper to make. Also, many governments offer support because of environmental concerns. This has made solar panels much more popular. The amount of solar power being installed is growing very fast, by about 30% each year in places like Germany, Japan, California, and New Jersey.
Images for kids
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Dynamos and engine installed at Edison General Electric Company, New York 1895
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Wind turbines often help generate electricity along with other power methods.
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Large dams, like Hoover Dam in the United States, can provide huge amounts of hydroelectric power. It can produce 2.07 gigawatts of power.
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A large generator with its spinning part (rotor) removed.
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Big dams such as Three Gorges Dam in China can provide lots of hydroelectric power. It has a 22.5 gigawatt capability.
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This diagram shows how energy flows through a power plant.
See also
In Spanish: Generación de energía eléctrica para niños
