Green Hydrogen is Clean Energy Storage. Turquoise Hydrogen is a Clean Energy Source.

  • Adam Kay
  • While green hydrogen has been vaulted into the spotlight by incentives in the Inflation Reduction Act intended to bolster ongoing natural gas industry efforts to decrease emissions, much less attention has been paid to its cousin turquoise hydrogen. Thanks to recent commercialization of turquoise hydrogen, however, this is likely to change.

    Hydrogen is all the same from a molecular perspective. The color system describes how it was produced (for more information on the classification system for hydrogen, check out our piece “The Hydrogen Rainbow” for a comprehensive breakdown of the types of hydrogen). Green hydrogen is derived from water through a process called electrolysis, using renewable energy like wind, solar, or hydroelectric dams. Electrolysis splits the water molecule into its component hydrogen and oxygen molecules, harvesting the hydrogen for use in home appliances, electrical generation, industrial applications, or as an ammonium feedstock for fertilizer (for more on how natural gas and the gas distribution system is critical to America’s agricultural system, see our recent study “The Value of Natural Gas to U.S. Agriculture and Agrochemicals”).

    Turquoise hydrogen is different. It’s derived from natural gas using a process called pyrolysis, in which the natural gas is heated to approximately 900 degrees. In layman’s terms, this cooks the carbon out of it in solid form, creating synthetic graphite which has great value for a variety of industrial applications (to learn more about the value proposition of turquoise hydrogen, read our recent piece “It’s Time to Pay Attention to Turquoise Hydrogen”).

    There are important similarities between these types of hydrogen. Both types are carbon-neutral, providing energy without emissions. The hydrogen produced via either method has the same end uses. Because they are carbon neutral, both types are eligible for Inflation Reduction Act hydrogen production tax credits. However, the real distinction is in their fundamental purpose.

    Green hydrogen is energy storage. The natural gas distribution system delivers three times as much energy on the coldest day of the year as the electrical distribution system delivers on the hottest day. This is possible because this energy is stored as natural gas molecules in underground storage, to be consumed when we need it most. To avoid having to potentially triple our electrical distribution system, green hydrogen can use excess renewable energy produced at times of low demand to save energy for the colder months. Green hydrogen is the king of long-term carbon neutral energy storage – while batteries are perfectly adequate for periods of up to four hours, there are no batteries currently in existence or on the drawing board capable of saving the equivalent of months’ worth of electrical production for a period of many months. Indeed, California, the state which has made the most progress on installing battery storage, currently has enough battery capacity for one (1) minute of electrical consumption[i], making it clear that leveraging the gas distribution system for energy storage is an important accelerant for decarbonization.

    Turquoise hydrogen is an energy source, albeit one that can be stored as effectively as green hydrogen. The energy in it, which can be put to work on your behalf, comes from natural gas which is produced and transported using existing infrastructure. Pyrolysis makes it carbon neutral, while adding commercial value in the form of synthetic graphite. This allows us to use the incredible flexibility of natural gas production as a source of energy that can be ramped up and down as dictated by demand. Because of the IRA tax credits, the cost of producing turquoise hydrogen can actually be negative in many parts of the country, even before the sale of the hydrogen itself or the synthetic graphite, creating an incredible financial incentive for companies to scale production.

    So, is one type better than the other? The answer is no – lowering emissions will require both energy storage and zero-carbon energy production. Green and turquoise hydrogen are both critical tools for meeting America’s goals on climate while keeping energy prices – currently the lowest in the developed world thanks to our abundance of natural gas – affordable for customers.

    [i] Peter Zeihan, The End of the World is Just the Beginning