Hydrogen Basics

Hydrogen (H2) is an alternative fuel that can be produced from domestic resources. Although in its market infancy as a transportation fuel, government and industry are working towards clean, economical, and safe hydrogen production and distribution for use in fuel cell electric vehicles (FCEVs). Fuel cell electric vehicles are beginning to enter the consumer market in localized regions domestically and around the world. The market is also developing for buses, material handling equipment, ground support equipment, medium- and heavy-duty vehicles, and stationary applications. For more information, see fuel properties and the Hydrogen Analysis Resource Center.

Hydrogen is locked up in enormous quantities in water (H2O), hydrocarbons (such as methane, CH4), and other organic matter. One of the challenges of using hydrogen as a fuel comes from being able to efficiently extract hydrogen from these compounds.

Currently, steam reforming, or combining high-temperature steam with natural gas to extract hydrogen, accounts for the majority of the hydrogen produced in the United States. Hydrogen can also be produced from water through electrolysis, but this method is much more energy intensive. Renewable sources of energy, such as wind or solar, can be used as the energy source to produce hydrogen—avoiding harmful emissions from other kinds of energy production.

Almost all of the hydrogen produced in the U.S. each year is used for refining petroleum, treating metals, producing fertilizer, and processing foods.

Although the production of hydrogen may generate emissions affecting air quality, depending on the source, a fuel cell electric vehicle running on hydrogen emits water vapor and warm air as exhaust and is considered a zero-emission vehicle. Major research and development efforts are aimed at making these vehicles and their infrastructure practical for widespread use and have led to the initial rollout of limited production vehicles in the consumer market.

Learn more about hydrogen and fuel cells from the Fuel Cell Technologies Office.

Hydrogen as an Alternative Fuel

Hydrogen is considered an alternative fuel under the Energy Policy Act of 1992. The interest in hydrogen as an alternative transportation fuel stems from its ability to power fuel cells in zero-emission electric vehicles, its potential for domestic production, and the fuel cell's potential for high efficiency. In fact, a fuel cell coupled with an electric motor is two to three times more efficient than an internal combustion engine running on gasoline. Hydrogen can also serve as fuel for internal combustion engines, but unlike with fuel cells, will produce tailpipe emissions and is less efficient. Learn more about fuel cells.

The energy in 2.2 pounds (1 kilogram) of hydrogen gas contains about the same as the energy in 1 gallon (6.2 pounds, 2.8 kilograms) of gasoline. Because hydrogen has a low volumetric energy density, additional steps are needed to store enough hydrogen onboard FCEVs to achieve the driving range of conventional vehicles. Most current applications use high-pressure tanks capable of storing hydrogen at either 5,000 or 10,000 psi. Other storage technologies are under development, including bonding hydrogen chemically with a material such as metal hydride, or low-temperature sorbent materials. Learn more about hydrogen storage.

Chart with different-size bars showing the relative volume needed for various hydrogen storage methods to achieve a greater than 300 mile driving range. At top is the shortest bar, representing 20 gallons of gasoline. Below this bar is a bar of equal length representing the year 2015 target for hydrogen storage. Below the 2015 target bar are five more bars, starting with a bar representing the volume of liquid hydrogen required, which is more than twice as long as the 2015 target bar. The rest of the bars increase in length--with each bar longer than the one above it--in the following order, representing the increasing volumes required to enable a 300-mile range: chemical hydrides, compressed 10,000 psi, metal hydrides, and compressed 5,000 psi.

Source: Hydrogen.energy.gov

California is leading the nation in funding and building hydrogen fueling stations for fuel cell electric vehicles. At the end of 2015, there were five retail hydrogen stations open to the public, 10 retail stations in commissioning stages, and 36 in various stages of construction or planning. California continues to fund station building efforts towards their goal of 100 stations. There are additional non-retail stations in California and throughout the country serving fuel cell electric vehicles, including buses, for research or demonstration purposes. Vehicle manufacturers are also beginning to offer FCEVs to consumers who live in regions where these hydrogen stations exist. By the end of 2016, there should be around 50 public hydrogen stations available nationwide. Find hydrogen fueling stations near you.