To produce hydrogen, it must be separated from the other elements in the molecules where it occurs. Hydrogen can be produced from many different sources in different ways to use as a fuel. The two most common methods for producing hydrogen are steam-methane reforming and electrolysis (splitting water with electricity). Researchers are exploring other hydrogen production methods, or pathways.
Steam-methane reforming is a widely used method of commercial hydrogen production
Steam-methane reforming accounts for nearly all commercially produced hydrogen in the United States. Commercial hydrogen producers and petroleum refineries use steam-methane reforming to separate hydrogen atoms from carbon atoms in methane (CH4). In steam-methane reforming, high-temperature steam (1,300°F to 1,800°F) under 3 bar–25 bar pressure (1 bar = 14.5 pounds per square inch) reacts with methane in the presence of a catalyst to produce hydrogen, carbon monoxide, and a relatively small amount of carbon dioxide (CO2).
Industrial facilities and petroleum refineries primarily use natural gas as the methane source for hydrogen production. Several fuel cell power plants in the United States treat and use landfill gas (biogas) as hydrogen source. Biofuels and petroleum fuels are also potential hydrogen sources.
Electrolysis uses electricity to produce hydrogen
Electrolysis is a process that splits hydrogen from water using an electric current. Electrolysis is commonly used in high school science classes to demonstrate chemical reactions and hydrogen production. On a large, commercial scale, the process may be referred to as power-to-gas, where power is electricity and hydrogen is gas. Electrolysis itself does not produce any byproducts or emissions other than hydrogen and oxygen. The electricity for electrolysis is currently provided by the electric power grid, which is supplied with a mix of renewable sources, nuclear energy, and fossil fuels.
Other methods of hydrogen production
Research is underway to develop other ways to produce hydrogen, including:
- Thermochemical processes to convert biomass into gas or liquids and to separate the hydrogen
- Photolytic processes that use solar energy to split water into hydrogen and oxygen
- Biological processes that use microbes, such as bacteria and microalgae, to produce hydrogen through biological reactions
Clean hydrogen production
The U.S. Department of Energy (DOE) supports source-neutral hydrogen production pathways and does not use a color code that is based on the hydrogen source, production technology, and carbon capture, which some producers, marketers, and other organizations use to categorize hydrogen. DOE's Hydrogen Program includes a number of programs by participating DOE program offices for clean hydrogen production to meet the requirements of the Infrastructure Investment and Jobs Act (Section 40315), also called the Bipartisan Infrastructure Law, and align with the Inflation Reduction Act (Section 13204). Two of the major DOE initiatives are:
Last updated: June 23, 2023.