Hydrogen not so clean some scientists warn.

By Margaret Munro
CanWest News Service

VANCOUVER — Hydrogen fuel, long held up as a squeaky clean form of alternative energy, may eat holes in the Earth?s protective ozone layer, say atmospheric scientists.

In a report in the journal Science today, the researchers warn widespread use of hydrogen could make the upper atmosphere cooler and cloudier and make the ozone hole deeper, wider, and more persistent.

Billions of dollars are being invested internationally on hydrogen-fuel systems to power automobiles and industry. Proponents — including most of the 1,100 delegates at a hydrogen-fuel conference here this week — maintain hydrogen will pave the way to a much cleaner future. The only byproduct of hydrogen, they like to say, is water produced when hydrogen combines with oxygen to generate power.

Dr. Yuk Yung and his colleagues at the California Institute of Technology say it is not quite so simple.  In a hydrogen-fuelled world, they predict huge volumes of the gas would escape into the air and waft up into in the upper reaches of Earth's atmosphere.  The hydrogen would get into the stratosphere, which is normally very dry, and produce water vapour and stratospheric clouds that could cool the climate. It would also, the scientist say, trigger re actions that eat away at ozone, which helps protect the Earth from the sun's harmful radiation.

The ozone layer has already been so seriously eroded by chiorofluorocarbons (CFCs) — long used as refrigerants and propellants in spray cans — that an international treaty is in place to curb their use.  Yung said hydrogen is not as destructive as CFCs, but could have a significant impact.

The scientists estimate 10 to 20 per cent of hydrogen (H2) produced as fuel would escape into the air. This means between 60 and 120-trillion grams of manmade hydrogen could be inadvertently loaded into the atmosphere each year if hydrogen takes over as a fuel. “More or less dramatic scenarios are equally imaginable, but clearly the potential impact on the (atmosphere's) H2 cycle is great,” they say.

Yung says the hydrogen would not be a health concern, though he and his colleagues caution it could have “unforeseen” effects on soil microbes which use hydrogen as a nutrient. The ‘more significant impact, they say, would be in the stratosphere, which starts about 16 kilometres above the ground.

Tom McElroy, a senior atmospheric scientist with Environment Canada, agrees hydrogen could create problems in the stratosphere. “ They're raising a valid point.” says McElroy, a leading authority on ozone depletion. “These kind of impacts certainly need to be taken seriously and looked at carefully.”  He is not, however, convinced so much hydrogen will leak into the atmosphere. “I'd be extremely surprised if the leakage rates got anywhere near the levels they are talking about:" says McElroy, who expects industry would try to prevent the fuel from disappearing into thin air. “But it's a good devil's advocate positibn to alert us to the danger"

The California researchers say their leakage estimates are based on losses seen in the commercial transportation of hydrogen today. 

Stratospheric pollution is not the only potential environmental impact of hydrogen.   Production of hydrogen gas often entails generation of large amounts of carbon dioxide — the leading pollutant associated with global warming.  Hydrogen fuel is created through electrolysis which requires electricity.

Hydrogen not so clean some scientists warn

Star Phoenix,  June 13, 2022

Comment by Gerald Regnitter, webmaster:  (Note also that this article does not consider the implications of what source of electrical energy is used to generate the hydrogen gas.  In Saskatchewan, if current SaskPower policies are followed, that would increase burning of coal and create even more pollution issues.  Hydrogen fuel use is only as "green" as the energy source that generated it. )