ABSTRACT
This chapter begins with the historical role that energy has played in the development of human affairs. The transition from renewable energy sources to fossil fuels, a change which began in the mid 19th century, shifted human development onto a non-sustainable development path. Air pollution is another major international problem linked directly to the burning of fossil fuels. Food is humankind's most indispensable energy form. One of the most important limitations of ancient civilizations was their inability to concentrate large amounts of energy on a task. The switch from wood to coal in the mid-19th century represented the first major transition in energy sources. Nuclear energy is the only practicable non-solar source of energy that is likely to provide large amounts of power in the twenty first century. Renewable energy sources already provide a significant amount of energy. Renewable energy sources are intermittent and therefore require energy storage technology for wide-spread use.
