What Is Hydrogen?
Source: NASA (Public Domain)
Did You Know?
Hydrogen is the lightest element and is a gas at normal temperature and pressure. Hydrogen condenses to a liquid at temperatures of -423° Fahrenheit (-253° Celsius).
Hydrogen is the simplest element. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars like the sun are made primarily of hydrogen.
The sun is basically a giant ball of hydrogen and helium gases. In the sun's core, 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 originally came from the sun's radiant energy.
Hydrogen gas is so much lighter than air that it rises fast and is quickly ejected from the atmosphere. This is why hydrogen as a gas (H2) is not found by itself on Earth. It is found only in compound form with other elements. Hydrogen combined with oxygen, is water (H2O). Hydrogen combined with carbon forms different compounds, including methane (CH4), coal, and petroleum. Hydrogen is also found in all growing things — for example, biomass. It is also an abundant element in the Earth's crust.
Hydrogen has the highest energy content of any common fuel by weight (about three times more than gasoline), but the lowest energy content by volume (about four times less than gasoline).
Hydrogen Is an Energy Carrier
Energy carriers move energy in a useable form from one place to another. Electricity is the most well-known energy carrier. We use electricity to move the energy in coal, uranium, and other energy sources from power plants to homes and businesses. We also use electricity to move the energy in flowing water from hydropower dams to consumers. For many energy needs, it is much easier to use electricity than the energy sources themselves.
Like electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen is not currently widely used, but it has potential as an energy carrier in the future. Hydrogen can be produced from a variety of resources (water, fossil fuels, or biomass) and is a byproduct of other chemical processes.