Researchers from Stanford University conducted a study that found a clean U.S. hydrogen economy is viable, but to be successful, policymakers will need to create a comprehensive strategy and clear ten-year plan.

According to the study, strong hydrogen infrastructure is critical to making clean hydrogen a viable energy option. Hydrogen infrastructure includes production, transport, storage, use and economic viability. All of these areas need to be clean for the overall process to be considered clean energy.

70 million metric tons of hydrogen are produced around the world every year and the U.S. contributes 1/7^th of the total. Almost all of the hydrogen produced is considered grey hydrogen. With grey hydrogen, ten kilograms of CO2 baggage per kilogram of hydrogen is produced. Currently, there is no clean hydrogen economy.

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There are a few hydrogen options on the market that are promising and more sustainable than grey hydrogen, but each type has its caveats. Blue hydrogen involves capturing CO2 and reducing emissions, creates hydrogen with less greenhouse output. But currently, blue hydrogen costs 50 percent more than gray hydrogen, not including the cost of developing pipelines and sequestration systems to transport and store unwanted CO2. CO2 capture costs need to be reduced for blue hydrogen to be completely clean and viable.

Another kind of hydrogen is called green hydrogen. Green hydrogen uses electricity and electrolyzers to split water into its elements without greenhouse gas byproducts. This hydrogen costs four to six dollars per kilogram but researchers say that the cost could be as low as two dollars per kilogram with a reduction in carbon-free electricity and electrolyzer costs.

Turquoise hydrogen is another option. This hydrogen is gathered through methane pyrolysis. To gather turquoise hydrogen, methane is cracked to generate greenhouse gas-free hydrogen. The solid carbon co-product created in this process could be sold to help offset costs. The quantity of solid carbon produced, though, would exceed current demand and new markets would need to be created to give this carbon a use.

Hydrogen is very promising for a variety of applications including transportation, chemical reduction of captured CO2, long-duration energy storage, chemical reductants for steel and metallurgy, and as high-temperature industrial heat for glass and cement production. All of the previously mentioned hydrogen options are promising, but their caveats need to be addressed before they can be implemented through a clear plan.

This research was published in Joule.