As we saw in Part 1 of this series, natural gas is increasingly in the crosshairs of city, state, and, potentially, even national regulators seeking more climate-friendly energy solutions. However, gas suppliers have an opportunity to contribute to these efforts rather than being targeted by them, in the form of “green gas.” In that post we discussed the first type of green gas, renewable natural gas (RNG). This time around we’ll take a look at the second, renewable hydrogen (RH).
Hailing Hydrogen
Hydrogen has long been touted as having the potential to play a major role in energy supply. In 1874, Jules Verne envisioned hydrogen furnishing “an inexhaustible source of heat and light,” that would replace coal. Fifty years later, the renowned chemist J.B.S. Haldane suggested using large hydrogen plants to store excess wind-energy. Around fifty years after that, in 1970, the electrochemist John Bockris would more fully develop a similar proposal that largely replaced wind energy with solar and nuclear power in what he dubbed the “hydrogen economy.”
Yet another half-century on, enthusiasm for hydrogen fuels is waxing once again. In 2022, the small Utah town of Delta closed its coal plant and embarked on the largest hydrogen storage project to date. In May, the Norwegian company Nel announced plans to build a “gigafactory” in Michigan intended to supply upwards of 4 gigawatts of hydrogen power annually. And earlier this month, the Biden administration followed through on early signals that hydrogen would play a significant role in its clean energy plan by selecting seven winning “hydrogen hub” proposals from across the U.S. (out of around 60 total). The winners are receiving in the neighborhood of $1 billion each to develop of regional networks of infrastructure and industry to accelerate incorporation of green hydrogen fuels into the American energy system.
This all paints a rosy picture, but there are two major questions with respect to the promise of hydrogen as a green gas replacement for natural gas.
Is it green?
The major byproduct of hydrogen consumption (the only byproduct under ideal conditions) is water, and so it is a clean fuel. Clean, but not necessarily green. A significant difference between hydrogen fuels and natural gas (renewable or not) is that hydrogen is an energy carrier rather than an energy source since free hydrogen (H2) is all but non-existent in nature. The idea of a hydrogen economy has always been to produce H2 by using electricity to split water, H2O in a process called electrolysis. Powering that process with solar, wind, or the like then yields a clean fuel that can readily store and transport renewable energy—“green hydrogen.”
The reality of the hydrogen industry is currently quite different, however. A 2020 DOE report estimated that only 1% of domestic hydrogen (and 2% global) is produced by electrolysis. While green hydrogen can also be produced using bigas or thermal conversion of biomass (like RNG), the overwhelming majority of hydrogen production comes from natural gas reforming. That process extracts H2 from the methane in natural gas to produce “grey hydrogen” (or, “blue hydrogen” if combined with carbon capture). For this reason, some environmentalists are actually wary of hydrogen, concerned that it will do as much harm as good by extending the use of fossil fuels.
While not ideal, there are still significant advantages to grey hydrogen. According to the DOE, when considering the entire process from fuel production to consumption, using grey hydrogen to power fuel cell electric vehicles halves total greenhouse gas emissions compared to gas-powered vehicles. However, that brings us to our second question.
Is it gas?
The DOE’s estimate above is for the use of hydrogen in the form of electrochemical fuel cells, not gas. Indeed, much of the excitement about hydrogen fuel has centered on the use of fuel cells, particularly to decarbonize the transport sector. For instance, Energy.gov’s Hydrogen Fuel Basics page focuses exclusively on fuel cells.
Is it going to happen? (Yes!)
While it is important to recognize concerns about current hydrogen production and the extent to which excitement about hydrogen is driven by interest in fuel cells, it is also important to recognize that the promise of RH as a green gas far outstrips its problems. A recent review article notes that “Hydrogen has potential to fill certain energy supply requirements that may not be easily met using battery electric storage, for example for gas boilers in the home, as a fuel for heavy-duty/long-distance vehicles, off-road machinery, back-up capacity for grid electrical supply and as a fuel for global shipping and aviation.” Gas-based storage projects like that in Delta, Utah are of increasing importance as the green energy sector wrestles with the intermittent nature of many renewable resources. And even hydrogen for use in fuel cells needs to be transported, largely by adapting current natural gas transmission infrastructure.
Advances are certainly needed in greening hydrogen production. But, of course, that is a major goal of the hydrogen hub initiative, and Nel’s Michigan plant is part of it’s goal to make green hydrogen as cheap to produce as fossil fuel-derived hydrogen by 2025.
In sum, while it is hard to say exactly to what extent the increasingly climate-friendly energy sector will constitute a “hydrogen economy,” it is easy to see that RH will play some significant role, and gas suppliers are well-advised to consider the part that they can play as the demand for natural gas inevitably dwindles.