Published on EGEE 401: Energy in a Changing World (https://www.e-education.psu.edu/egee401)

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Energy Concepts

Energy is neither created nor destroyed. Energy is in everything. It exists in many different forms, morphing easily from one form to another. It is heat, light, motion and the possibility of motion! It holds the molecules in our body together, and separates the seas from the skies. It is lightning and wind and sunshine and waves and oil and plants. It is your body and mine. Before we talk about energy in the sense of the energy industry—the preparation and delivery of energy for an intended use at a specific location, it’s useful to consider the innate qualities and properties of energy.

In science, we simply define energy as “the ability to do work.” We can measure energy. If we define a system to measure—say a ball at the top of a ramp, then let the ball roll down the ramp and bump into something, or use a stretched rubber band to turn a paddle in water, or eat a dozen donuts—these are all forms of energy morphing into another form of energy. The total amount of energy before and after is exactly the same, though it is in different forms. The energy that was in the ball is now in the obstacle it hit. The energy from the rubber band is now in the slightly warmed water. The donuts are in your belly, as energy to be used or stored.

Energy exists in many different forms. Some forms of energy can help us do things we need or want to do. When it is in the form of heat, energy warms our homes, bath water, and cars. When it is in the form of motion, energy carries us places in cars and trains and airplanes. When it is in the form of electricity, it gives us light and runs our appliances and electronics. We need energy in a useful form, when and where we need it, and in the right quantity.

If you are in an electric car, a gallon of diesel fuel will not help. If your house is heated with oil, electricity will not warm you. If your office runs on electricity, a load of coal isn’t going to turn equipment on. Sunshine and waterfalls won’t start your car, and wind won’t run the dishwasher. BUT, if we match the form and timing of the energy with your needs, all of these things could be true.

Energy in a changing world, then, is about both ends of the stick. The form of the energy delivered and how it is used. Much of the energy used in this country, and around the world, is in the form of electricity. We don’t get electricity directly from nature, by catching lightning in a jar, but instead we get it by transforming energy from other forms into the form of electricity. We do this because electricity is a convenient form of energy to move and manage. When the electricity gets to where it is going, it is then transformed into another form of energy to do whatever it is we need it to do—turn on our lights, heat our water, charge our batteries, play our music. Similarly, the engines that run our cars and equipment convert energy from one form to another—from the chemical energy in a fuel into motion. And, all along the way, it takes energy to manage and deliver energy!

Throughout this course, we are going to refer back to the natural processes underlying the energy industry—energy in its many natural forms and the basic process of transforming one form to another. In the first two lessons, we are going to review the many forms of energy and the basic transformation processes. Then, we will talk about how they relate to our energy industry, the environment and our security.

Reading Assignment

Visit the U.S. Energy Information Administration site, Energy Explained [1].

  • Read "What is Energy" and all subpages.
  • Read "Units and Calculators" and all subpages.
  • Read "U.S. Energy Facts" and all subpages (notice multiple tabs on first page).

 


Source URL: https://www.e-education.psu.edu/egee401/content/p1_p2.html

Links
[1] http://tonto.eia.doe.gov/energyexplained/index.cfm?page=about_home