Hydrogen is the simplest element known to man. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars are made primarily of hydrogen. The sun is pretty much a giant ball of hydrogen and helium gas. In the core of the sun, hydrogen atoms combine to form helium atoms. This process, called fusion, gives off radiant energy. This radiant energy sustains life on earth. It gives us light and makes plants grow. It makes the wind blow and rain fall. It is stored as chemical energy in fossil fuels.

Most of the energy we use today came from the sun's radiant energy. Hydrogen gas is lighter than air and, as a result, it rises in the atmosphere. This is why hydrogen as a gas is not found by itself on earth. It is found only in compound form with other elements. Hydrogen combined with oxygen, is water. Hydrogen combined with carbon, forms different compounds such as methane, coal, and petroleum. Hydrogen is also found in all growing things...biomass. It is also an abundant element in the earth's crust. Hydrogen has the highest energy content of any common fuel by weight, but the lowest energy content by volume. It is the lightest element, and it is a gas at normal temperature and pressure.

Like electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen is not widely used today but it has great potential as an energy carrier in the future. Hydrogen can be produced from a variety of resources (water, fossil fuels, biomass) and is a byproduct of other chemical processes. Unlike electricity, large quantities of hydrogen can be easily stored to be used in the future. Hydrogen can also be used in places where it’s hard to use electricity. Hydrogen can store the energy until it’s needed and can be moved to where it’s needed.

Scientists have even discovered that some algae and bacteria give off hydrogen. Steam reforming is currently the least expensive method of producing hydrogen and accounts for about 95 percent of the hydrogen produced in the United States. It is used in industries to separate hydrogen atoms from carbon atoms in methane. Because methane is a fossil fuel, the process of steam reforming results in greenhouse gas emissions that are linked with global warming. Electrolysis is a process that splits hydrogen from water. It results in no emissions but it is currently a very expensive process. New technologies are being developed all the time.

Hydrogen has great potential as an eco-friendly clean energy fuel and as a way to reduce reliance on foreign energy sources. Before hydrogen can play a bigger energy role and become a widely used alternative to gasoline, many new facilities and systems must be built. We will need facilities to make hydrogen, store it, and move it. We will need economical hydrogen powered fuel cells. And consumers will need the technology and the education to safely use it.

To read our chapter that covers all of our renewable energy sources, please visit our clean renewable energy page.