The element Hydrogen (H2) is composed of a single proton and a single electron, making it the simplest element in the universe and the most abundant element – about 90 percent of the visible universe is believed to be composed of hydrogen. Hydrogen is the raw fuel that most stars 'burn' to produce energy and it is found in the earth’s crust and oceans.[1] Hydrogen occurs naturally on earth only in compound form with other elements. The hydrogen has to be separated out to be used as a source of energy or fuel.[2]

Hydrogen is stored in water (H2O), hydrocarbons, such as methane (CH4), and other organic matter. Currently, most hydrogen is produced from natural gas, and today almost all of the hydrogen produced in the U.S. is used for refining petroleum, treating metals, producing fertilizer, and processing foods. But hydrogen has opportunities in both the stationary and transportation energy sectors. And hydrogen can be produced from carbon-free renewable feedstocks.[3]

Primary Uses of Hydrogen 

While the largest uses of hydrogen are petroleum refining and fertilizer production, transportation and utilities represent emerging markets. [4]

Source: U.S. Department of Energy, 2020[5]

Hydrogen Energy as Transportation Fuel

Although the National Aeronautics and Space Administration (NASA) began using liquid hydrogen in the 1950s as a rocket fuel[6] hydrogen is in its infancy as a ground transportation fuel. Government and industry are working to develop 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 and the market is also developing for buses, material handling equipment (such as forklifts), ground support equipment, medium- and heavy-duty vehicles, and stationary applications. FCEVs do not emit harmful greenhouse gases.[7]

Renewable Hydrogen Definition

While FCEVs do not emit harmful greenhouse gases, a carbon footprint does exist from the natural gas feedstock and steam methane reforming (SMR) process used currently to produce hydrogen. The carbon footprint of FCEVs can be reduced by using renewable feedstock as the input for SMR-produced hydrogen. Renewable hydrogen has been defined as any hydrogen produced using renewable energy or electricity derived from renewable sources. California, the early hydrogen adopter state, accepts the following as renewable hydrogen energy feedstocks: biomass, solar thermal, photovoltaic, wind, geothermal, fuel cells using renewable fuels, small hydroelectric generation of 30 megawatts or less, digester gas, municipal solid waste conversion, landfill gas, ocean wave, ocean thermal, or tidal current.[8]

Global Potential for Future Use of Hydrogen

Hydrogen holds long term potential in many sectors, as is captured in the graphic below, culled from the DOE 2020 report Hydrogen Strategy, Enabling a Low Carb Economy.

Source: U.S. Department of Energy, 2020[9]

Updated June 2022 by Erin Bennett