Hydrogen is the miracle element. It can power fuel cells that make electricity, leaving nothing behind but water and little heat. In theory, if humanity used hydrogen to meet all its energy needs, a pollution-free environment would be ours to enjoy forever and a day. What a wonderful world that would be. What a glorious time to be free! A new report from CICERO makes that dream less certain.
Ever since the Fukushima disaster, Japan has been the principal advocate for a hydrogen economy. Its government has doled out copious quantities of money to prod manufacturers like Toyota and Honda to build hydrogen-powered cars. Many of us in the CleanTechnica community have slammed Toyota (and to a lesser extent Honda) over and over again for putting their electric car plans on hold while they pursue the hydrogen dream, but we have to understand that when the government pushes for something, it almost always gets what it wants.
The reality is quite a bit different, however. Fossil fuel companies have crowded aboard the hydrogen bandwagon, convinced it is the solution they have been praying for — a technology that will allow them to keep producing methane gas while telling the public it is pollution free. We know that is pure, unadulterated horse puckey, but it is music to the ears of the gullible.
Now CICERO is out with a report that says while the use of hydrogen may result in no emissions, leakage from the hydrogen distribution system can be twelve times as destructive to the environment as carbon dioxide. The study was published June 7, 2023, in the journal Communications Earth & Environment. According to Phys.org, the study fills a gap in our knowledge about the climate effects of hydrogen, a central technology in the energy transition.
Hydrogen is not a greenhouse gas, but its chemical reactions in the atmosphere affect greenhouse gases like methane, ozone, and stratospheric water vapor. Therefore, emissions of hydrogen can lead to increased global warming despite its lack of direct radiative properties. The research was led by Dr. Maria Sand, a senior scientist at CICERO, and her colleagues in conjunction with researchers in the UK, France, and the US.
“The climate effects of hydrogen have been an under-researched topic. However, a few papers based on single model studies confirm our estimated global warming potential over 100 years (GWP100) of 11.6,” said Sand. “We used five different atmospheric chemistry models and investigated changes in atmospheric methane, ozone and stratospheric water vapor.”
“Hydrogen interacts with various biogeochemical processes. In our estimates, we have included soil uptake, photochemical production of hydrogen, the lifetimes of hydrogen and methane, and the interactions between hydrogen and methane,” said Sand.
According to Sand, the study is the most comprehensive assessment of the climate effect of hydrogen to date, thanks to the advanced and novel use of existing climate models. “We have assessed the uncertainties, and our study forms a robust foundation for political decision-making on hydrogen. A global warming potential of 11.6 is significant, and our study clearly shows the importance of reducing hydrogen leaks. We lack the technology to monitor and detect hydrogen leaks at the scale needed, but new technology is being developed as the industry adapts.”
The potential benefit of switching to a hydrogen economy will depend on the magnitude of hydrogen leakages and to what extent hydrogen replaces fossil fuels. “There are still many open questions, and our group will continue to expand our knowledge to ensure timely and accurate decision-making on a key mitigation technology,” Sand said.
Unpacking The CICERO Hydrogen Report
“With increasing global interest in molecular hydrogen to replace fossil fuels, more attention is being paid to potential leakages of hydrogen into the atmosphere and its environmental consequences. Hydrogen is not directly a greenhouse gas, but its chemical reactions change the abundances of the greenhouse gases methane, ozone, and stratospheric water vapor, as well as aerosols,” the CICERO researchers report.
“We estimate a hydrogen GWP100 of 11.6 ± 2.8 (one standard deviation). The uncertainty range covers soil uptake, photochemical production of hydrogen, the lifetimes of hydrogen and methane, and the hydroxyl radical feedback on methane and hydrogen. The hydrogen induced changes are robust across the different models. It will be important to keep hydrogen leakages at a minimum to accomplish the benefits of switching to a hydrogen economy.”
Readers who want to dig into the science are encouraged to go directly to the study, which for once is not behind a paywall. For the rest of us, here is the gist of the findings:
When hydrogen is produced, transported, stored, and used, some fraction of the gas will leak to the atmosphere. In the existing value chain, there is very little data on the magnitude of these leakages and how this will evolve in a future growing hydrogen economy. Sources of hydrogen include biomass burning, fossil fuel combustion, biological nitrogen fixation, atmospheric photo-oxidation of methane and volatile organic compounds, and possibly geological sources.
Hydrogen is removed from the atmosphere by biological uptake in soils and atmospheric oxidation by the hydroxyl radical (OH). The largest term, and the largest uncertainty term in the atmospheric hydrogen budget is the soil uptake, which in most studies accounts for 65–85% of the total hydrogen sink. The atmospheric lifetime of hydrogen, defined as the total atmospheric burden divided by the total sinks, is about 2 years.
Any Earth system perturbation that impacts tropospheric chemistry creates a complex chain of events that alter radiatively active atmospheric species, such as methane, ozone, and aerosols, and hence perturbs Earth’s radiative budget. Hydrogen is involved in atmospheric chemical reactions that affect the lifetime and abundances of other gases that have an impact on the climate and is thus such an indirect greenhouse gas.
Four main climate impacts are associated with increased hydrogen levels: (1) a longer methane lifetime and hence increased methane abundances, (2) an enhanced production of tropospheric ozone and changes in stratospheric ozone, (3) an increased stratospheric water vapor production, and (4) changes in the production of certain aerosols. The most important reaction driving these impacts is the destruction of hydrogen by OH: H2+OH→H2O+H
OH is the most important and powerful oxidant in the atmosphere. Oxidation by OH is the major sink of hydrogen, methane, and other compounds in the atmosphere. The levels of OH in the atmosphere depend on other gases, most notably methane, nitrogen oxides , carbon monoxide and VOCs. All these processes are highly coupled and lead to chemical feedback processes. Oxidation of methane and VOCs by OH also provides an important atmospheric source of hydrogen.
The change in chemistry caused by both the uptake of OH and production of H in reaction can lead to changes in ozone. In the troposphere, the production of water vapor is negligible compared to the natural water cycle, but in the stratosphere this reaction can affect the water vapor levels. Changes in OH, ozone, and other oxidants may also affect the formation of particles, especially sulfate, secondary organic aerosols, and nitrate, and alter their size distributions.
Hydrogen, Science And Reality
Now we know that hydrogen is not the magic dust we can sprinkle around to make the climate crisis go away and stop bothering us. That leads to some possible insights into other technologies touted as cures for our fossil fuel addiction, particularly geoengineering the atmosphere.
The interactions between the earth, the air, and the oceans are fantastically complex. Anyone who claims to know what the effect of shooting some sulfur dioxide particles into the upper atmosphere or iron oxide pellets into the ocean with a reasonable degree of certainty is either a charlatan or a liar.
There is only one solution — stop extracting, transporting, refining, and burning fossil fuels. The corollary to that is to not start using new technologies that are worse for the environment. Unless and until the production, transportation, and storage of green hydrogen can be made leak free, the dream of a hydrogen economy is a foolish effort filled with false promises.
We know what to do to preserve the Earth. It’s time to get on with it.
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