How Clean is ‘Clean’ Hydrogen?

The Democrats’ new climate bill, which was passed by the US Senate on Sunday, has been described as “transformative” and “game-changing.” But perhaps the most apt word is “shocking”—in a good way, for once. According to analysis after analysis, it’s become clear that this is what the United States needs to make good on promises to fight climate change. For climate scientists long accustomed to shouting into the wind—or at least their Twitter feeds—it’s something to celebrate. “We’re so pumped about this bill,” says Morgan Rote, director of US climate at the Environmental Defense Fund.

In a bill as sprawling as this one, compromises will always be necessary. Provisions for new oil and gas leases are the obvious doozy, slotted in to appease Senator Joe Manchin (D- West Virginia). So are potential compromises on environmental permitting, which include ample deference to oil and gas pipelines. But perhaps nothing is as confusing—or as potentially far-reaching and long-lasting—as the bill’s generous incentives for “clean” hydrogen. If this bill allows more fossil fuel development, it’s with the tacit hope that the industry is facing an inevitable decline. The theory is that it’ll kick the bucket anyway as demand for oil and gas withers, outmoded and outcompeted by cleaner sources of energy. Hydrogen? It’s here to stay.

That push isn’t new, exactly. The provisions, which are modeled after those that helped kickstart solar investment decades ago, build on other recent efforts, like an $8 billion investment in the Biden administration’s 2021 infrastructure bill to build Hydrogen Hubs across the country that can serve as epicenters of the fuel’s production and distribution. Those were widely derided as potential “bridges to nowhere,” without incentives that would ramp up hydrogen supply and demand. This bill has them, with production tax credits that get more generous depending on how “clean” the hydrogen is.

Using hydrogen is undoubtedly clean—it is combined with oxygen to produce water vapor and energy and has applications for powering utilities, homes, and cars. But producing it can involve dirtier sources of energy, often natural gas, which contains climate-warming methane. One reason hydrogen has backers in the oil and gas industry is because the fuel, which can come in gas or liquid forms, allows for the repurposing of fossil fuel infrastructure that is poised to be abandoned during the shift to renewables.

Energy experts often use a rainbow full of buzzwords to describe the relative virtues of these hydrogen-making processes. First there’s “gray” hydrogen, the dominant method of production today, which combines methane and water vapor through a process called “steam reforming.” In the process, waste carbon dioxide is released into the atmosphere.

Next comes “blue” hydrogen, which is the same thing, except it involves capturing some of that CO₂ and burying it underground. Other processes involve splitting apart water molecules using electricity, which is known as electrolysis. It’s “green” when that electricity is produced with renewable energy and pink when it’s nuclear (a potential lifeline for struggling plants). And there’s turquoise, yellow, and brown, too—but let’s not belabor the point.