Hydrogen Basics

Hydrogen (H2) is an alternative fuel that can be produced from diverse domestic resources. Although it's just getting started in the market as a transportation fuel, government and industry are working toward clean, economical, and safe hydrogen production and distribution for widespread use in fuel cell electric vehicles (FCEVs). FCEVs 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 abundant in our environment. It's stored 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 it from these compounds.

Currently, steam reforming, 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 FCEV 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 production vehicles in areas such as northern and southern California.

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, its fast filling time, and the fuel cell's 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. However, unlike FCEVs, these produce tailpipe emissions and are less efficient. Learn more about fuel cells.

The energy in 2.2 pounds (1 kilogram) of hydrogen gas is 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, it is stored onboard a vehicle as a compressed gas 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. Retail dispensers can fill these tanks in about 5 minutes. 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 FCEVs. At the end of 2016, there were 25 retail hydrogen stations open to the public, 4 retail stations in commissioning stages, and 20 more in various stages of construction or planning. Additionally, the California Energy Commission released a Notice of Proposed Awards (NOPA) on February 17, 2017 in the amount of $33 million to develop 16 more retail hydrogen stations. California continues to provide funding for building the infrastructure, with the Energy Commission having authorization to allocate up to $20 million per year through 2024 until there are at least 100 operational stations. There are additional non-retail stations in California and throughout the country serving FCEVs, including buses, for research or demonstration purposes. Vehicle manufacturers are also beginning to offer FCEVs to consumers who live in regions where hydrogen stations exist. By the end of 2017, there are expected to be more than 50 public hydrogen stations available nationwide. Find hydrogen fueling stations across the U.S.