What is Hydrogen and How is it Produced? (Text Alternative Version)

This is the text alternative transcript for the U.S. Hydrogen Program podcast titled: What is Hydrogen and How is it Produced? The media files can be accessed on the DOE Hydrogen Program Media Files page.

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Welcome to this edition of The Hydrogen Report. I'm Mike Weiner.

In this edition of the Hydrogen Report, we'll introduce you to hydrogen and how it can be produced as part of America's energy mix.

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Hydrogen is often — mistakenly — called an energy source. Arlene Anderson of the U.S. Department of Energy explains:

"Well like electricity, hydrogen is an energy carrier. It can store and deliver energy in a usable form, but it must be generated from compounds that contain it. In other words, we need to produce hydrogen from other things. But we can do that using many different resources found here in the U.S. — fossil fuels like natural gas and coal, nuclear energy, and renewable energy resources like biomass, as well as solar, wind, hydro-electric, and geothermal energy. This great diversity of energy supply means we don't need to rely on any single energy resource or on a foreign source of energy — and that hydrogen can be produced just about anywhere."

Hydrogen can be produced at large central plants far from the end-user — people like you and me. It can also be produced at medium-sized plants closer to where it is needed, or even at the point of end-use, like refueling stations or where it is used to provide stationary power. This is called distributed production.

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Today, energy companies in the U.S. produce about 9 million tons of hydrogen each year. Nearly all of this is used for industrial purposes like petroleum refining - but just for context, it's enough hydrogen to fuel about 34 million cars - there are well over 200 million cars on the road today in the U.S. About 95% of our hydrogen is made using natural gas. In a process called reforming, hydrogen is produced from the methane in natural gas using high-temperature steam.

"Currently, using natural gas the most economical way to produce hydrogen is using natural gas. With proven and cost-effective technology, producing hydrogen using natural gas can generate sufficient quantities of hydrogen for near-term use. But there are trade-offs. We don't have an endless supply of natural gas in the U.S., so over the long-term, large-scale production of hydrogen using natural gas is not an attractive option. We'd be trading our dependence on imported petroleum for a dependence on imported natural gas."

If we're not going to rely on natural gas, how else can we produce hydrogen?

One way — which, scaled-down, is also a popular classroom experiment — is electrolysis. Here, we use an electrical current to split water into hydrogen and oxygen. The electricity can come from the electrical grid, but ideally, it's generated using renewables like wind and solar power with virtually no emissions. When produced this way, hydrogen can also serve as a storage medium for variable renewable power. By producing both hydrogen and electricity at a wind farm, for example, hydrogen made with wind power can be stored and used to generate electricity when wind power isn't available — when the wind is not blowing.

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Hydrogen can be made from other renewables like biomass — things like crop or forest residues and switchgrass. Like natural gas, biofuels such as ethanol — which is rapidly ramping up in production and use today — can also be reformed to produce hydrogen. And in fact, the growing infrastructure for ethanol could play an important role in the availability of renewable hydrogen in the future.

We can also make hydrogen directly from biomass in a process called gasification, which converts biomass into a gas mixture by applying heat in the presence of steam. A similar process can be used with coal, which is regarded as important for the future, mostly because we have so much of it. The U.S. has more proven coal reserves than any other country in the world. The key is to produce hydrogen from coal cleanly and efficiently. Arlene Anderson says it's important to note that we're not talking about using coal to make electricity to make hydrogen — but rather producing it directly by gasification.

"Carbon dioxide is produced in the process, but research is under way to develop what's called sequestration technology that can capture and store the byproduct carbon dioxide so it's not released into the atmosphere."

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There's also an important role for nuclear energy in the hydrogen future. We can produce hydrogen by electrolysis using high temperature steam from a nuclear reactor — the higher temperature reduces the amount of electricity required to split the water molecules. Another technology under research uses high temperature heat from a nuclear reactor or solar concentrator to drive a series of chemical reactions that produce hydrogen from water. The chemicals are reused within each cycle, creating a closed loop that consumes only water and produces hydrogen and oxygen and no other emissions.

There are also other longer-term technologies that use light energy to split water into hydrogen and oxygen.

"Just as plants produce oxygen during photosynthesis, certain algae and bacteria produce hydrogen as a byproduct of their natural metabolic processes. There are also special semiconductors that absorb sunlight and use the light energy to dissociate water molecules into hydrogen and oxygen. Both technologies are in the very early stages of research — but they have long-term potential for hydrogen production with minimal environmental impact."

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With so many different ways to produce hydrogen, you might ask…why aren't we producing more? One reason is the currently low demand, but the other, bigger reason is cost. Research has reduced the cost of distributed hydrogen production from natural gas to about $3 per gallon of gasoline equivalent. Generally speaking, though, more is needed to bring costs down.

"Regarding the variety of production technologies, R&D today is focused on reducing the cost of capital equipment, operations, and maintenance, as well as improving efficiency. We're also focused on developing carbon sequestration technology to ensure clean coal-to-hydrogen production. Our R&D is also focused on reducing the cost of renewable energy technologies like wind and solar, and improving agricultural handling practices to reduce the cost of biomass used in hydrogen production."

Thanks for listening. If you'd like to learn more about hydrogen — and increase your H2IQ — visit hydrogen.energy.gov. And be sure to listen for future episodes of The Hydrogen Report.