IntroductionAmerica is built on available energyThere is nothing wrong with America than the faith, love of freedom, intelligence and energy of its citizens cannot cure Dwight D. Eisenhower US general and Republican politician (1890 - 1969) When President Eisenhower spoke these words, I don't imagine he would have imagined the critical role that energy plays in 21st century America. Everywhere we look, energy is transformed and consumed. Our cars need it. Our emails to family use it. The strawberries we eat in Wisconsin arrived here, thanks to the energy used in transportation systems. America has always thrived on an abundance of energy. Early American Energy Sources Many of the pre-Revolutionary portraits show famous people standing by a fireplace. Wood was the abundant source of energy in the pre-revolutionary years in America. Trees were freely available in the early years of our country. In the 1600s, 1700s, and 1800s, wood was by far the dominant energy source, but coal grew in use. But as scientists dug deeper into sources of energy and matter, in 1776 Cavendish discovered hydrogen. His experiments isolated this most fundamental of elements, setting the stage for wider use of hydrogen in the 21st century. Energy Sources of 1900 In the first half of the century, coal became the dominant energy source in America. During 1900, when the population increased nearly 4-fold, energy consumption increased 10-fold. The use of petroleum energy grew dramatically and became the dominant energy source by the end of the century. By the end of the century, energy consumption in America had quadrupled compared to 1800. Partly this was due to the increasing population in America, but mostly due to the need for social changes brought about by World Wars I and II. Energy Sources of the 2000s In this early part of the 21st century, petroleum energy remains the dominant energy source. Additionally, due to the changing nature of our industries, natural gas has become much more common as an energy source than coal or wood. But a growing energy resource is hydrogen. What is hydrogen? The name hydrogen comes from the Greek language: Hydro: water, genes: formation. As we noted earlier, Henry Cavendish is credited with isolating pure hydrogen and defining some of its key properties. Some of these properties include that it is: Colorless Odorless Non-metallic Univalent Highly flammable Diatomic gas. It is the most abundant element in the universe.