Tag: hydrogen

“Right now, nearly all of the existing hydrogen produced in the US today isn’t clean at all. Ninety-five percent of it is “gray hydrogen,” produced using a method called steam methane reforming. This process uses steam to heat methane derived from natural gas until it separates into a mixture of carbon monoxide, carbon dioxide, and hydrogen gas molecules. This process is incredibly energy-intensive and gives the gray hydrogen production industry a carbon footprint the size of the United Kingdom and Indonesia combined. Gray hydrogen is mostly used for industrial purposes like refining petroleum and metals as well as producing chemicals, fertilizer, and in rarer cases, fuel for vehicles.
Blue hydrogen is a tiny but growing subset of the industry. Similar to gray hydrogen, blue hydrogen production uses steam methane reforming, which means that it also relies on natural gas. But for blue hydrogen, carbon capture and storage and other monitoring attempts are introduced to limit leakage of methane, a powerful greenhouse gas, which in theory minimizes its impact on climate change. And carbon capture and storage technologies haven’t been proven at the scale for blue hydrogen to capture over the 90 percent of emissions needed to deliver climate benefits.

A third and very buzzworthy option is green hydrogen. Producing green hydrogen employs a process called electrolysis, which uses an electrolyte, anode, and cathode to create a chemical reaction that splits water into hydrogen and oxygen molecules. No carbon capture is needed here, as no fossil fuels are involved in the process. As the name implies, this is the cleanest way to produce hydrogen — if it relies entirely on renewables for the electricity to power the process. It is currently very expensive and requires subsidies to compete with dirtier hydrogen options.

One other consideration with these types of hydrogen is the energy needed to produce them. Both blue and green hydrogen could be used in similar ways and work as a clean energy solution, except a lot rides on how the hydrogen is made. If energy derived from fossil fuels powers the production of any type of hydrogen, that could undermine carbon cuts. For green hydrogen, specifically, electrolysis is a problem area because it’s so power-hungry. So it’s essential that the electricity that powers the process comes from renewables, like solar, wind, and nuclear. It also matters where the renewables come from. One worry environmentalists have is that new hydrogen facilities will simply draw from existing solar and wind, eating up a lot of the clean electricity we already have.”

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“There are even more colors of hydrogen, each of which refers to a different production method. So while the phrase “clean hydrogen” is thrown around a lot, it’s not always clear what it’s referring to.”

https://www.vox.com/climate/23900109/hydrogen-green-energy-hubs-biden