Potential as a Fuel Rises When Paired with Renewable Energy (“Green Hydrogen”)
Hydrogen (H) is the most abundant element in the universe; it is typically found bonded to carbon (such as hydrocarbons in petroleum) and oxygen (as in water). Hydrogen is not widely used as a fuel at this time. However, given its energy density, molecular hydrogen (H2) has potential to be used as fuel, especially in conjunction with developments in renewable energy. Below are some facts on hydrogen as an element and fuel.
Hydrogen (H2) condenses into a liquid at -423°F (-253°C), about just 20°C above absolute zero—the lowest possible temperature.
In comparison to gasoline, hydrogen has almost three times the energy density by mass (120 megajoules (MJ) per kilogram to 44 MJ per kilogram) but only about a fourth by volume (8 MJ per liter to 32 MJ per liter).
As of 2020, 99% of hydrogen production in the US is from fossil fuels (95% from steam-methane reformation and 4% from coal gasification). These methods are known as “gray hydrogen” from not removing the resulting carbon dioxide.
When steam-methane reformation is combined with carbon capture and storage, it is termed “blue hydrogen.”
Only 1% of US hydrogen production is from electrolysis, a form of “green hydrogen” that does not use fossil fuels nor produce carbon dioxide (aside from energy costs).
Global hydrogen use reached 95 megatons in 2022, with the highest use by China (29%). This was followed by North America (17%), the Middle East (13%), India (9%), Europe (8%), and the “rest of the world” (24%).
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