ABSTRACT
Some energy sources offer the prospect of being inexhaustible. Water and wind are two such sources. Some more sources include biomass, solar energy, and nuclear fusion (all to be discussed in later chapters). However, the common sources of energy that people in many countries rely on are electricity and liquid fuels for transportation. These usually come from fossil fuel sources. Most of us take for granted an unlimited supply of electricity; if there is any limitation at all, it is in our ingenuity for plugging appliance upon appliance into the available outlets. Similarly, we presume the ability to purchase unlimited amounts of gasoline or diesel fuel, anywhere, anytime. But fossil fuels are not inexhaustible. And, unlike biomass, fossil fuels cannot be regenerated on human time scales. Someday, in some sense of the term, we will run out.
