With hydrogen, ‘clean’ should be colorblind
As the world looks for ways to decarbonize, hydrogen has emerged as a leading candidate for this transition. In addition to filling an important role for electric power reliability, hydrogen offers carbon-free energy for large-capacity transport and other hard-to-decarbonize industrial applications.
The potential market for hydrogen is huge: hundreds of billions of dollars, and hundreds of thousands of jobs, in the U.S. alone.
Early efforts to brand hydrogen by color — primarily blue, green, pink or gray — have led to confusion over the end goal of a decarbonized economy. Recently, the U.S. Department of Energy has started using the term “clean hydrogen.” That’s a goal-focused characterization agnostic as to method of production, and encourages technology innovation and environmental progress. Clean hydrogen focuses on the environmental qualities of the final product, regardless of the technologies used.
For kick-starting a clean hydrogen economy, the Southwestern U.S., and New Mexico in particular, have many outstanding attributes that make it uniquely well-suited to lead in this new era. New Mexico’s abundant wind and solar resources, low-cost natural gas and subsurface capabilities for hydrogen storage and carbon sequestration can support a wide range of hydrogen production technologies, provided the hydrogen is made cleanly.
Hydrogen’s greenhouse gas attributes (and subsequent environmental value) are best measured by “life-cycle carbon intensity.” A life-cycle analysis is a “cradle to grave” assessment that facilitates more consistent comparisons across energy technologies.
Life-cycle carbon intensity is not a new concept; it’s frequently used in comparing technologies. It’s used in the Environmental Protection Agency’s assessment methodology for its renewable fuel standard as well as California’s low-carbon fuel standard. It makes these markets more credible and environmentally efficient.
For different hydrogen production methods, carbon intensity takes into account all of the carbon dioxide and other greenhouse gasses throughout the life cycle of the fuel, including upstream emissions. As such, hydrogen derived from natural gas with carbon capture would need to account for any fugitive methane emissions that might be associated with the feedstock supply, as well as any uncaptured portion of CO2 emissions in the production process.
Similarly, hydrogen produced using water electrolysis powered by renewable energy would need to account for the greenhouse gas impacts going into the production of the critical minerals, water procurement and purification, solar panels and wind turbines involved in the energy and water inputs.
One cannot conclude that one hydrogen production method is in all cases better or worse than another. A life-cycle carbon intensity can ensure a full and unbiased accounting.
Importantly, a carbon-intensity measure does more than provide an impartial assessment across hydrogen production methods; it also creates incentives for improving hydrogen production methods over time. Under traditional command-and-control regulatory approaches, producers see advantage in bare-minimum compliance; anything more might add costs but not value.
In contrast, under a life-cycle carbon intensity methodology, the cleaner the producer can make the production process (including upstream processes), the more value the product will have. The regulatory script has now been flipped; the “race to the bottom” mentality has now been replaced by incentives for continuous improvement, with concurrent GHG benefits.
Clean hydrogen holds enormous potential for a decarbonized economy. A life-cycle carbon intensity measure can help get us there most efficiently.