Hydrogen is a secondary source of energy. It stores and transports energy produced from other resources (fossil fuels, water, and biomass).
Hydrogen as an Energy Carrier
Because hydrogen does not exist freely in nature and is only produced from other sources of energy, it is known as an energy carrier. It is a clean-burning fuel, and when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product.
Hydrogen can be made directly from fossil fuels or biomass, or it can be produced by passing electricity through water, breaking the water into its constituent components of hydrogen and oxygen. Some envision a future "hydrogen economy," where hydrogen is produced from a variety of energy sources, stored for later use, piped to where it is needed, and then converted cleanly into heat and electricity.
Most hydrogen production today is by steam reforming natural gas. But natural gas is already a good fuel and one that is rapidly becoming scarcer and more expensive. It is also a fossil fuel, so the carbon dioxide released in the reformation process adds to the greenhouse effect. Hydrogen has very high energy for its weight, but very low energy for its volume, so new technology is needed to store and transport it. And fuel cell technology is still in early development, needing improvements in efficiency and durability.
Making a Hydrogen Economy a Reality
The challenges NREL researchers are working on to help make a hydrogen economy a reality include:
Improving fuel cell technology and materials needed for fuel cells.
Developing technology to efficiently and cost-effectively make hydrogen from renewable energy sources.
Developing technology to efficiently and cost-effectively store and transport hydrogen.
For more information about hydrogen, visit the following resources:
Hydrogen Fuel Basics
U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy
Energy Kids Hydrogen Basics
U.S. Energy Information Administration Energy Kids