U.S. Department of Energy - Energy Efficiency and Renewable Energy
Alternative Fuels and Advanced Vehicles Data Center
Hydrogen Production
Hydrogen is an energy carrier, not an energy source. Energy is required to separate it from other compounds. Once produced, hydrogen stores energy until it is delivered in a usable form, such as hydrogen gas delivered into a fuel cell.
Hydrogen can be produced from diverse, domestic resources including fossil fuels, nuclear energy, biomass, and other renewable energy technologies. The environmental impact and energy efficiency of hydrogen depends greatly on how it is produced.
The following are some ways to produce hydrogen. Many are in the early stages of development. For more information, see Hydrogen Production (PDF 331 KB). Download Adobe Reader.
Natural gas reforming—"synthesis gas" is created by reacting natural gas with high-temperature steam or by partial oxidation. The synthesis gas is then reacted with water to produce hydrogen
Renewable electrolysis—an electric current generated by renewable energy technologies, such as wind or solar, splits water into hydrogen and oxygen
Gasification—Coal or biomass is converted into gaseous components and then into synthesis gas, which is reacted with steam to produce hydrogen
Renewable liquid reforming—renewable liquid fuels such as ethanol are reacted with high-temperature steam to produce hydrogen near the point of end-use
Nuclear high-temperature electrolysis—heat from a nuclear reactor is used to improve the efficiency of water electrolysis to produce hydrogen
High-temperature thermochemical water-splitting—high temperatures generated by solar concentrators or nuclear reactors drive chemical reactions that split water to produce hydrogen
Photobiological—microbes such as green algae consume water in the presence of sunlight, producing hydrogen as a byproduct
Photoelectrochemical—photoelectrochemical systems produce hydrogen from water using special semiconductors and energy from sunlight
DOE-sponsored research is investigating the ability of green algae to produce hydrogen directly from water and sunlight.
Natural gas reforming using steam accounts for about 95% of the approximately 9 million tons of hydrogen produced in the United States annually. This level of hydrogen production could fuel more than 34 million cars. The major hydrogen-producing states are California, Louisiana, and Texas. Almost all of the hydrogen produced in the United States is used for refining petroleum, treating metals, producing fertilizer, and processing foods.
The primary challenge for hydrogen production is reducing the cost of production technologies to make the resulting hydrogen cost competitive with conventional transportation fuels. Government and industry research and development projects are reducing the cost as well as the environmental impacts of hydrogen production technologies. Learn more from the U.S. Department of Energy Hydrogen, Fuel Cells & Infrastructure Technologies Program and National Renewable Energy Laboratory Hydrogen and Fuel Cells Research Web sites.
To learn how hydrogen is distributed, see the Hydrogen Distribution page.