Hydrogen Production and Distribution
Hydrogen is an energy carrier—not an energy source—and energy is required to separate it from other compounds. Once it is separated and produced, hydrogen stores energy until it is delivered in a usable form, such as a gas delivered into a fuel cell.
Hydrogen can be produced from diverse, domestic resources including fossil fuels, biomass, and other renewable energy technologies. The environmental impact and energy efficiency of hydrogen depends greatly on how it is produced. Some projects are underway to decrease costs associated with hydrogen production.
There are a number of ways to produce hydrogen:
Natural Gas Reforming: Synthesis gas, a mixture of hydrogen, carbon monoxide, and a small amount of carbon dioxide, is created by reacting natural gas with high-temperature steam or by partial oxidation. The carbon monoxide is reacted with water to produce additional hydrogen. This method is the cheapest, most efficient, and most common for producing 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 reacted with high-temperature steam and oxygen in a pressurized gasifier and converted into gaseous components. The resulting synthesis gas contains hydrogen and carbon monoxide, which is reacted with steam to produce more hydrogen.
Fermentation: Biomass is converted into sugar-rich feedstocks that can be fermented to produce hydrogen.
A number of hydrogen production methods are in development:
High-Temperature Water Splitting: High temperatures generated by solar concentrators or nuclear reactors drive chemical reactions that split water to produce hydrogen.
Photobiological Water Splitting: Microbes, such as green algae, consume water in the presence of sunlight, producing hydrogen as a byproduct.
Photoelectrochemical Water Splitting: Photoelectrochemical systems produce hydrogen from water using special semiconductors and energy from 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. Lean more about hydrogen production from the Fuel Cell Technologies Program and the National Renewable Energy Laboratory.
Most hydrogen used in the United States is produced at or close to where it is used—typically at large industrial sites. As a result, there is not yet an effective infrastructure for distributing hydrogen to the nationwide network of fueling stations required for the widespread use of fuel cell vehicles.
Currently, hydrogen is distributed through three methods:
Pipeline: This least-expensive way to deliver large volumes of hydrogen is limited—with only about 700 miles of U.S. pipelines located near large petroleum refineries and chemical plants in Illinois, California, and the Gulf Coast.
High-Pressure Tube Trailers: Transporting compressed hydrogen gas by truck, railcar, ship, or barge in high-pressure tube trailers is expensive and used primarily for distances of 200 miles or less.
Liquefied Hydrogen Tankers: Cryogenic liquefaction enables hydrogen to be transported more efficiently over longer distances by truck, railcar, ship, or barge compared with using high-pressure tube trailers, even though the liquefaction process is expensive.
Creating an infrastructure for hydrogen distribution and delivery to thousands of individual fueling stations presents many challenges. Because hydrogen contains less energy per unit volume than gasoline, transporting, storing, and delivering it to the point of end-use is more expensive. Building a new hydrogen pipeline network involves high initial capital costs, and hydrogen's properties present unique challenges to pipeline materials and compressor design. However, because hydrogen can be produced from a wide variety of resources, regional or even local production of hydrogen can maximize use of local resources and minimize distribution challenges.
There are tradeoffs between centralized and distributed production to consider. Producing hydrogen centrally in large plants cuts production costs but boosts distribution costs. Producing hydrogen at the point of end-use—at fueling stations, for example—cuts distribution costs but boosts production costs because of relatively low production volumes.
Government and industry research and development projects are overcoming the barriers to efficient hydrogen distribution. Learn more about hydrogen distribution from the Fuel Cell Technologies Program.