FUEL CELL TECHNOLOGIES OFFICE

Hydrogen can be produced using a variety of resources including biomass, hydro, wind, solar, geothermal, nuclear, coal with carbon capture, utilization and storage, and natural gas. This diversity of sources makes hydrogen a promising energy carrier and enables hydrogen production almost anywhere in the world.

Hydrogen Production diversity of potential supply sources is Natural Gas Reforming an important reason why hydrogen is Hydrogen can be produced from natural Hydrogen is an energy carrier, not an such a promising energy carrier. gas using high-temperature steam. This energy source—hydrogen stores and process, called steam methane reforming, Hydrogen can be produced at large accounts for about 95% of the hydrogen delivers energy in a usable form, but central plants, at medium scale semi- used today in the U.S. Another method, it must be produced from hydrogen- central plants, or in small distributed called partial oxidation, produces hydro- containing compounds. units located at or very near the point gen by burning methane in air. Both steam reforming and partial oxidation produce a Hydrogen can be produced using of use, such as at refueling stations or “synthesis gas” or “syn gas,” which is then diverse, domestic resources including stationary power sites. reacted with additional steam to produce a fossil fuels, such as natural gas and higher hydrogen content gas stream. coal (preferentially with carbon How Is Hydrogen capture, utilization, and storage); Produced? Renewable Electrolysis biomass grown from renewable, Electrolysis uses an electric current to Researchers are developing a wide range non-food crops; or using nuclear split water into hydrogen and oxygen. The of technologies to produce hydrogen energy and renewable energy sources, electricity required can be generated using economically from a variety of resources such as wind, solar, geothermal, and any of a number of resources. However, in environmentally friendly ways. hydroelectric power to split water. This to minimize greenhouse gas emissions, FUEL CELL TECHNOLOGIES OFFICE

electricity generation using renewable series of chemical reactions to split water To reduce overall hydrogen cost, research energy technologies (such as wind, solar, into hydrogen and oxygen. All of the inter- is focused on improving the efficiency of geothermal, and hydroelectric power), mediate process chemicals are recycled hydrogen production technologies as well nuclear energy, or natural gas and coal within the process. as reducing the cost of capital equipment, with carbon capture, utilization, and stor- operations, and maintenance. Biological age are preferred. Certain microbes, such as green algae Gasification and cyanobacteria, produce hydrogen by Research Directions Gasification is a process in which coal or splitting water in the presence of sunlight Hydrogen production technologies are biomass is converted into gaseous compo- as a byproduct of their natural metabolic in various stages of development. Some nents by applying heat under pressure and processes. Other microbes can extract technologies, such as steam methane in the presence of air/oxygen and steam. hydrogen directly from biomass. reforming, are already commercial and can be used in the near term. Others, such A subsequent series of chemical reactions Photoelectrochemical (PEC) as high-temperature thermochemical produces a syn gas, which is then reacted Hydrogen can be produced directly from water-splitting, biological, and photoelec- with steam to produce a gas stream with water using sunlight and a special class trochemical, are in early stages of labora- an increased hydrogen concentration that of semiconductor materials. These highly tory development and considered potential then can be separated and purified. With specialized semiconductors absorb sun- pathways for the long-term. carbon capture and storage, hydrogen light and use the light energy to directly can be produced directly from coal with split water molecules into hydrogen and Related research includes developing new near-zero greenhouse gas emissions. oxygen. hydrogen delivery methods and infra- Since growing biomass consumes carbon structure, improving carbon sequestration dioxide from the atmosphere, producing What Are the Challenges? technology to ensure that coal-based hydrogen through biomass gasification The greatest challenge for hydrogen hydrogen production releases almost no results in near-zero net greenhouse gas production, particularly from renewable greenhouse gas emissions, and improving emissions. resources, is providing hydrogen that biomass growth, harvesting, and handling Renewable Liquid Reforming is cost competitive. For transportation, to reduce the cost of biomass resources Biomass can also be processed to make a key driver for energy independence, used in hydrogen production. renewable liquid fuels, such as ethanol or hydrogen must be cost-competitive with bio-oil, which are relatively convenient to conventional fuels and technologies on a For More Information transport and can be reacted with high- per-mile basis. This means that the cost of More information on the Fuel Cell temperature steam to produce hydrogen at hydrogen—regardless of the production Technologies Office is available athttp:// or near the point of use. Researchers are technology, and including the cost of de- www.hydrogenandfuelcells.energy.gov. also exploring a variation of this technol- livery—must be less than $4/gallon gaso- ogy known as aqueous-phase reforming. line equivalent (untaxed and dispensed). Nuclear High-Temperature Electrolysis Heat from a nuclear reactor can be used to improve the efficiency of water electroly- sis to produce hydrogen. By increasing the temperature of the water, less electricity is required to split it into hydrogen and oxygen, which reduces the total energy required. High-Temperature Thermochemical Water-Splitting Another water-splitting method uses high temperatures generated by solar concen- trators (mirrors that focus and intensify sunlight) or nuclear reactors to drive a

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