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 Hydrogen can be produced at Natural Gas Reforming large central plants, at medium Hydrogen can be produced from natural Hydrogen can be produced using scale semicentral plants, or in small gas using high-temperature steam. This diverse, domestic resources. Fossil distributed units located at or very process, called steam methane reforming, fuels, such as natural gas and coal, can near the point of use, such as at accounts for about 95% of the hydrogen be converted to produce hydrogen, refueling stations or stationary power used today in the United States. Another and the use of carbon capture, sites. method, called partial oxidation, produces utilization, and storage can reduce the One kg of hydrogen has the same hydrogen by combusting methane in carbon footprint of these processes. air. Both steam reforming and partial Hydrogen can also be produced from energy content as one gallon of oxidation produce a synthesis gas or syn low carbon and renewable resources, gasoline, on a lower heating value gas, which is then reacted with additional including biomass grown from basis. steam to produce a higher hydrogen non-food crops and splitting water content gas stream. using electricity from wind, solar, How Is Hydrogen geothermal, nuclear, and hydroelectric. Produced? This diversity of potential supply Gasification sources is an important reason why Researchers are developing a wide range Gasification is a process in which coal hydrogen is such a promising energy of technologies to economically produce or biomass is converted into gaseous carrier. hydrogen from a variety of resources in components by applying heat under environmentally friendly ways. pressure and in the presence of air/ FUEL CELL TECHNOLOGIES OFFICE

oxygen and steam. A subsequent series intensify sunlight) to drive a series dispensed). To reduce overall hydrogen of chemical reactions produces syn gas, of chemical reactions to split water cost, research is focused on improving which is then reacted with steam to into hydrogen and oxygen. All of the the efficiency and lifetime of hydrogen produce a gas stream with an increased intermediate process chemicals are production technologies as well as hydrogen concentration that then can recycled within the process. reducing the cost of capital equipment, be separated and purified. With carbon operations, and maintenance. Photoelectrochemical (PEC) capture and storage, hydrogen can be Hydrogen can be produced directly produced directly from coal with near-zero from water using sunlight and a special Research Directions greenhouse gas emissions. Since growing class of semiconductor materials. These Hydrogen production technologies are biomass consumes carbon dioxide from highly specialized semiconductors in various stages of development. Some the atmosphere, producing hydrogen absorb sunlight and use the light energy technologies, such as steam methane through biomass gasification results in to directly split water molecules into reforming, are already commercial and near-zero net greenhouse gas emissions hydrogen and oxygen. can be used in the near-term. Others, such without carbon capture and storage. as solar thermochemical water-splitting, Biological Renewable Liquid Reforming photoelectrochemical, and biological are Certain microbes, such as green algae Biomass can also be processed to make in early stages of laboratory development and cyanobacteria, produce hydrogen by renewable liquid fuels, such as ethanol or and considered potential pathways for the splitting water in the presence of sunlight bio-oil, which are relatively convenient to long-term. as a byproduct of their natural metabolic transport and can be reacted with high- processes. Other microbes can extract Related research includes developing temperature steam to produce hydrogen hydrogen directly from biomass. new hydrogen delivery methods and at or near the point of use. Researchers infrastructure, improving carbon are also exploring a variation of this What Are the Challenges? sequestration technology to ensure that technology known as aqueous-phase coal-based hydrogen production releases reforming. The greatest challenge for hydrogen production, particularly from renewable almost no greenhouse gas emissions, and Electrolysis resources, is providing hydrogen at improving biomass growth, harvesting, Electrolysis uses an electric current to lower cost. For transportation fuel cells, and handling to reduce the cost of biomass split water into hydrogen and oxygen. a key driver for energy independence, resources used in hydrogen production. The electricity can be generated in several hydrogen must be cost-competitive with ways. However, to minimize greenhouse conventional fuels and technologies on a For More Information gas emissions, electricity generation using per-mile basis. This means that the cost of More information on the Fuel Cell renewable energy technologies (such as hydrogen—regardless of the production Technologies Office is available wind, solar, geothermal, and hydroelectric technology—must be less than $4/ at http://energy.gov/eere/fuelcells/ power), nuclear energy, or natural gas and gallon gasoline equivalent (untaxed and fuel-cell-technologies-office. coal with carbon capture, utilization, and storage are preferred. High-Temperature Electrolysis Examples of H2 Production Approaches: Heat from industrial processes such as a Technologies, Scales, and Timeframe nuclear reactor can be used to improve the efficiency of electrolysis 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. Solar Thermochemical Water-Splitting (STCH) Another water-splitting method uses high temperatures generated by solar concentrators (mirrors that focus and

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April 2016 Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% post consumer waste.