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​​​​​​​​​​​​​​​​​​​​Hydrogen, the most abundant element in the universe, is a versatile fuel that can be produced from a variety of sources, making it a promising option for transportation, electricity generation, and other hard-to-decarbonize industries.

What is hydrogen used for?

Hydrogen has many uses. Most hydrogen consumed in the United States is used in industrial processes such as petroleum refining, metal treatment, fertilizer production, and food processing.

Beyond industry, hydrogen can be used as an alternative fuel source in transportation. Like gasoline, hydrogen can be used to power a car, but with zero tailpipe emissions, making it an attractive solution to decarbonize the automotive industry. Currently, drivers of light-duty fuel cell electric vehicles (FCEVs) can fuel up at retail stations in less than five minutes and obtain a driving range of more than 300 miles. However, the infrastructure needed to expand the use of fuel cell vehicles is not yet established. Industry, government entities, and stakeholders across the nation are working to establish hydrogen refueling corridors, lower the costs, and increase production to prepare for the potential market. 

​The above are just a few of the many uses for hydrogen. Hydrogen is also used to fuel rockets, store and transport power, and even power entire power plants. Hydrogen has the potential to facilitate decarbonization of the electric power sector by storing excess generation from renewable energy sources when production is high and using it to generate electricity when renewable resources are limited or electricity demand is high.

How is hydrogen made?

There are several methods to make hydrogen; each is categorized via color. The most common method for hydrogen production is the thermal process of natural gas reforming (Grey/Blue hydrogen). This process can be done utilizing other hydrocarbon fuels such as gasified coal, gasified biomass, or renewable liquid fuels. Electrolysis (Pink/Green Hydrogen), is another method in which hydrogen molecules are separated from water using an electrolyzer. Below is a diagram that depicts the most common methods of hydrogen production by the level of greenhouse gas emissions they produced.​

In order from highest to lowest GHG emissions: brown/black, grey, blue, turquoise, pink, then green.





There are other less adopted methods like solar-driven and biomass processes. Solar-driven processes use light as the agent for hydrogen production while biological processes utilize microbes that break down organic matter like biomass or wastewater to produce hydrogen. Solar-driven processes include photoelectrochemical and solar thermochemical methods. Photoelectrochemical processes use specialized semiconductors to separate water into hydrogen and oxygen and solar thermochemical processes uses concentrated solar power to drive water splitting reactions. Photobiological processes use bacteria and green algae to produce hydrogen; these bacteria and algae use sunlight as their energy source, thus this process is both biological and solar-driven!

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