Energy Storage, 2nd Edition

Chapter 2Fundamentals of Energy

The concept of energy is elusive and mysterious. It is constantly being reexamined for greater understanding. It’s an idea or concept about which nearly everyone thinks they have some understanding. It is interesting to note how we refer to the idea by such phrases as “burning excess energy,” “using a lot of energy,” or someone “has a lot of energy,” as if it were a fuel of some sort. The repetition of the word, as with most concepts, conveys a vague feeling of comfort with the notion, that we indeed have a grasp of it. In this chapter, we discuss the concept of energy. We review the fundamentals of various types of energy including mechanical, electrical and chemical, and interject some historical perspectives of energy and its usage.

2.1 Classical Mechanics and Mechanical Energy

Frequently, in ordinary conversation or in more popular literature, the term energy is confused with or substituted for force. This confusion dates back many centuries beginning with human attempts to comprehend physical phenomena and the world around them. Even after the beginning of what is known as the scientific method, attributed to Galileo, much about the subject has confounded our comprehension. In the next pages we will address the issue of what energy is.

2.1.1 The Concept of Energy

We may never be actually able to observe the quantity named “energy,” but its effects are certainly and easily observable. Perhaps this also adds to the mystery of energy. Lindsay ...