SERC: Frequently Asked Questions About Hydrogen

What is hydrogen?
Hydrogen is a colorless, odorless, nontoxic gas. It is buoyant, extremely diffusive and thermally conductive. It burns with a clean, hot flame.

How is hydrogen produced?
Most hydrogen is produced today from natural gas (chiefly made up of methane) by the process of steam reformation. Since this process relies on a nonrenewable fossil fuel, it is not a viable long-term source of hydrogen. Generating hydrogen via reformation also adds carbon dioxide to the atmosphere.

Hydrogen can be made from renewable energy sources by the process of electrolysis. Electricity from solar, wind, or hydropower generators is supplied to an electrolyzer, which splits water into its constituent elements, hydrogen and oxygen. The overall process is:

Electricity + Water --> Hydrogen + Oxygen + Heat

Electrolysis using renewable electricity is sustainable, efficient (generally around 75%), and does not deplete natural resources. The small amount of water required (about 2 gallons of water produces hydrogen with the energy content of a gallon of gasoline) is returned to the environment when the hydrogen is used. The oxygen can also serve as a useful byproduct.

Why use hydrogen?
Hydrogen is a wonderful fuel. It can be used as a transportation fuel in cars, trucks, and planes. It can be burned in flameless, catalytic burners to produce heat for cooking and water and space heating in homes and for process heat in industries, just as we now use natural gas. And when used as a fuel for a fuel cell, it can produce electricity quietly, cleanly, and efficiently. Hydrogen combustion does not contribute to global warming, acid rain, or air pollution.

Hydrogen can serve as a storage medium for renewable energy. This is necessary since renewable sources are not always available (the sun doesn't always shine and the wind doesn't always blow). And since it is easily transported in pipelines, hydrogen can carry energy from resource rich areas (such as the sunny southwest or the windy northern plains) to other areas of the country.

Hydrogen can be "made in America." We could potentially supply all our energy needs using renewably generated hydrogen, eliminating our dependence on foreign countries and reducing the likelihood of future wars over dwindling oil reserves.

Is hydrogen safe?
Hydrogen is a fuel and as with any fuel, there can be dangers associated with its use. However, in many ways hydrogen is safer than the fuels we are accustomed to using, such as natural gas, propane, and gasoline. The reason for this is hydrogen's buoyancy and diffusivity. Any hydrogen leak dissipates extremely rapidly and does not linger to form explosive mixtures. Numerous industrial hydrogen systems have been in use for many years and have excellent safety records. (Read more about hydrogen safety.)

How much does it cost?
Renewably generated hydrogen is still expensive. Researchers estimate the cost of generating hydrogen from renewable sources to range from $9-$36 per gigajoule (by comparison, gasoline at $2 a gallon costs $16 per gigajoule), depending on the specific technology and varying economic discount rates*. This energy price range is roughly equivalent to one to four times the current rate Californians pay for natural gas. However, as the costs of solar and wind power continue to decrease, renewable hydrogen will become less expensive.

*Ogden, Joan and Joachim Nitsch. "Solar Hydrogen," from Renewable Energy: Sources for Fuels and Electricity, Edited by Thomas B. Johansson et al. Island Press, 1993.