Where Does Energy Come From?

What is energy?

Energy = the ability to do work! It takes energy to set cars in motion, to cool refrigerators, and to run factories. Anything that moves, plugs in, or creates heat or cold needs some kind of energy to make it work. (We are talking about human-made things here, not animals or plants; living things need different kinds of energy.)

Why is it important that we understand where energy comes from?

Making and using some sources of energy can hurt life on our planet. Making and using others does little or no harm. It’s important to know the difference.

Some sources of energy will eventually run out. (These are nonrenewable.) Others will never be used up. (These are renewable.) It’s important to know which sources we will be able to use in the future.

Let’s start by looking at two nonrenewable sources of energy. Once these are used up, there won’t be any more.

Nuclear Energy

You can probably think of a hundred ways in which you use electricity every day! There are many ways to produce electricity, and nuclear energy is one of them. To understand this source of energy, you first have to think about some basic science. Everything on Earth is made of tiny little particles called atoms. Part of each atom is something called a nucleus. Every nucleus contains energy. Scientists have figured out a way to split apart an atom’s nucleus to take some of its energy. To do this, they use the atoms from a metal called uranium. The energy that comes from splitting uranium atoms is used to produce electricity.

Today, there is a lot of uranium on Earth. But once we use up all that uranium, there won’t be any more. There is another problem with nuclear energy: The process of splitting the atoms produces dangerous waste. That waste must be stored safely away from humans for thousands of years.

Fossil Fuels

Fossil fuels are oil, natural gas, and coal. These fuels were formed from the rotting bodies of plants and animals that lived millions of years ago. Once all the oil, gas, and coal on our planet are used up, there won’t be any more.

Fossil fuels, like living things, contain a lot of carbon. When we burn fossil fuels, we are actually putting that carbon (along with oxygen, called carbon dioxide) into the atmosphere. The carbon dioxide stays high above Earth’s surface and acts like a blanket, causing our planet to get warmer. Carbon dioxide is just one of the greenhouse gases — there are many others. They are called greenhouse gases because they warm the Earth just as a greenhouse keeps plants warm.

Now let’s take a look at five renewable sources of energy. Remember, these never run out.

Solar Power

To produce this kind of energy, people “collect” sunlight and change it into electricity. It takes special equipment to do this, but once the equipment is made, solar energy is free. Collecting solar energy does not produce pollution, so it’s a “green” way to create electricity for everyday use. But since sunlight isn’t always available, the sun is not the most reliable source of energy.

Wind Power

Wind is a natural, clean, and inexpensive source of energy. Wind machines look like big fans. Instead of using electricity to turn the blades, the wind turns the blades and produces electricity! In order for this source of energy to be affordable, you need a reliable, steady source of wind.

Biomass Power

Did you ever imagine people would use garbage to produce energy? In fact, garbage and other organic materials, such as wood, the remains of plants and animals, and even manure (that’s cow poop!) can produce energy. That energy can be turned into electricity, heat, and transportation fuels.

Unfortunately, the process used to turn organic matter into energy can cause air pollution. It also releases greenhouse gases that contribute to global warming.

Geothermal Power

The word geothermal comes from the Greek words geo, meaning “Earth,” and therme, meaning “heat.” Geothermal energy comes from the natural heat inside the Earth. We can get this heat from hot springs, volcanoes, and reservoirs (big pools) of hot water below Earth’s surface. This source of energy has almost no negative effect on the environment. There are 49 geothermal power plants in the United States.

HydroPower

Moving water (from a waterfall or river) spins the blades of a turbine, which collects the energy and turns it into electricity. (A turbine looks like a big fan.) Some hydroelectric power plants are built where water flows naturally. Others rely on water flowing over a human-made dam. Some even use the tides or the power of waves.

Many people believe hydropower is the perfect fuel for creating electricity because it is a renewable, clean source of energy that does not leave waste products behind. Others don’t like the fact that rivers are dammed to create power plants. What do you think?

Scientists and inventors are working hard to create and discover new sources of renewable energy that won’t harm our planet.