The thing about hydrogen…..

Hearing a lot about hydrogen? It's the next "big thing", a green fuel, a gas, that can be made directly from cheap renewable solar and wind energy. It can be stored, transported and exported, offering Australia a key to future decarbonisation, replacement of fossil fuels, and global leadership as a renewable energy superpower.

What's more, where green electricity alone fails to replace a fossil fuel in certain "difficult-to-electrify" industrial processes like steel and fertiliser production, Green hydrogen will gallop to the rescue. (As it happens a horse called Hydrogen won the Victoria Derby at Flemington, Melbourne in 1951.)

Naturally for all these reasons various Australian industries are interested in hydrogen (the gas, not the horse). And governments are supporting and funding large R&D programs to improve ways of making Green hydrogen, like electrolysis, and applying it wherever industry sees opportunities to replace fossil fuels with green electricity.

Sounds great. But the thing about hydrogen … well, not everything is as it seems and there are good reasons to be concerned that expectations for hydrogen are too high. Primarily, hydrogen energy has already been a "big thing", several times, without much evidence of commercial success. Long gestation periods for new technologies are always a worry. The rapid greening of electricity supplies seems to have built confidence generally in green technology innovation. But electricity production was the easiest green target. The basic technologies had been known for decades.

It is informative to have a deeper look at hydrogen's recent history.

Arguably we are in a third wave of the hydrogen mania Professor John Bockris, a world famous electrochemist (and former colleague of mine), initiated in the 1960s. In 1975 he published a book Energy, the Solar-Hydrogen Alternative while he was at Flinders University, South Australia.

But nothing much happened.

In 2003 President George W Bush embraced a second wave when he announced $1.2 billion in research funding for developing clean hydrogen-powered automobiles. There's also a book about that, The Hype About Hydrogen – Fact and Fiction in the Race to Save the Climate, by Joseph J. Romm, who led the clean energy program at the U.S. Department of Energy for about 10 years.

The title says it all.

About the same time a third wave was rising in Australia. In 2003 the Australian Institute of Energy held a symposium The Hydrogen Economy – The Great Green Hope? (I spoke at it.) This is clearly the largest of the waves and is accelerating. Remember, there was hardly any interest or motivation relating to carbon emissions in the early days. Today that's the major driver and interest is now peaking.

The Australian government has a hydrogen vision and strategy and sees the need to support relevant technological advances. Government money is flowing, managed by ARENA, the Australian Renewable Energy Agency. There's $2 billion for a Hydrogen Headstart initiative to generate innovative technology for scaling up of Green hydrogen production and its use by industry to cut or eliminate fossil fuel consumption.

ARENA explains its involvement on its website. "Hydrogen is the most common chemical element in the universe" and a "clean fuel" that burns to give water without emitting carbon dioxide. Producing it with clean renewable electricity gives it a pristine Green pedigree. It will make Australia a "renewable energy super power" and help decarbonise our economy. It will generate exportable clean products, replace natural gas and LNG, and be a major export earner. One readily senses why government is interested.

There are downsides of course. On the hydrogen production side Australia lacks competitive advantage in hydrogen electrolyser technology. On the applications side the technologies that use hydrogen to replace coal and natural gas in heavy industries like steel and fertiliser production are still at the early stage.

Arguably the R&D challenges and risks are being underestimated by government. Lack of R&D successes will cost the taxpayer dearly. More generally, hydrogen and its potential role in the energy field are not widely understood. For example the claim "hydrogen is the most common chemical element in the universe" is popular for enhancing hydrogen's image. It may be true but is irrelevant.

The facts are that there are two "hydrogens". The one of interest is a flammable gas, burning to release its energy and forming water (H₂O). It is already an industrial chemical produced in quantity (globally around 90 million tonnes per annum) from natural gas mainly for use in the petrochemical, fertiliser and food industries. This hydrogen gas molecule comprises two atoms of the element hydrogen.

The "other hydrogen", the one so abundant in the universe, comprises hydrogen atoms. Our sun consists of about 75% such hydrogen.

For all practical purposes neither of those two forms of hydrogen exists naturally on Planet Earth. All our local hydrogen atoms are tied up tightly in chemical compounds, mainly water. Here, hydrogen the gas has to be made. That's the big difference between it and conventional fuels, which got their energy from naturally occurring materials. That energy nearly always originated from the sun.

The largest source of our hydrogen is natural gas, essentially methane (CH₄). Another source uses electrolysis and is generally restricted to sites where the cheapest hydroelectricity is available. Electrolysis involves the passage of electricity through electrically conductive solutions of salts etc. It is used widely in processes like chromium plating and copper electrowinning and refining. Electrolysis once yielded some 10% of the world's hydrogen. That seems to be declining but statistics are hard to find.

Electrolysis is expected to be the main method worldwide for manufacturing Green hydrogen. When the electricity is Green the hydrogen is Green.

Electrochemists (like me) understand what goes on in electrolysis. Electrochemistry is a relatively minor branch of chemistry. It will largely be a mystery to business people, politicians and the general public. Does that matter? It's hard to say. What's important is the availability of chemical technologists who do understand electrochemistry.

One set of ARENA hydrogen projects (there are 663 in total) aims to improve hydrogen production by electrolysis, already a mature industrial process. I have an old industrial electrochemistry textbook illustrating many ingenious electrolyser designs dating back over a century. There have of course been improvements. Modern advanced materials for electrodes, cells and separators are involved. Several specialist engineering firms still seem active in improvement and manufacture of novel electrolysers. It is hard to see where new Australian entrants encouraged by government funding could make an impact on electrolysis technology. We shall see.

Another vital aspect of the ARENA hydrogen program is the exploration of new industrial uses for green electricity, as in steel and fertiliser production. These will expand Green hydrogen's market prospects. ARENA also funds many projects on the industrial machinery and equipment needed for cooling, handling, reticulation, transport and storage of hydrogen, all of which are notoriously difficult and expensive.

What are the prospects of successful innovation in all these areas? I have a special interest in that question, and in general on the returns from scientific/industrial R&D. It was once my job as a CSIRO Divisional Chief (in the minerals and metal production field) to make decisions on projects for innovation in industrial processes. It was not academic research. We were dedicated to seeing our results in practical use. We engaged closely with industry to that end. I worked with scientists, technologists and engineers who lived for the day they could say their work and ideas were being used, profitably, by an Australian business. We knew such success was rare; that goes with the territory. Industrial research (the IR in CSIRO) is always risky. We learned to live with disappointment. Fortunately that line of work offers other rewards and sources of satisfaction.

Perhaps my experience has skewed my views but I fear that the outlook for Australia's expansive hydrogen R&D effort is not particularly encouraging. It would be good to see fewer projects and greater involvement of large firms with track records of relevant innovation.

Development efforts will need to face well-known and unavoidable energy losses in applications of synthetic Green hydrogen. All hydrogen production methods consume energy. When that hydrogen is put to use it yields less energy, often much less, than was consumed in its production.

Such efficiency penalties are well understood, in the literature at least. They were crisply summarised over 20 years ago by Dr Ulf Bossel, a Swiss engineer who pioneered hydrogen fuel cell research: "If renewable electricity is converted to hydrogen, and hydrogen is subsequently reconverted to electricity, then…only about 25% of the original electrical energy may be recovered by the consumer".

So in this primary application of hydrogen, synthesis of a Green fuel by electrolysis and subsequent use to generate clean electricity, three quarters of the initial energy may disappear (as waste heat). Bossel claimed, rightly, that it was much more efficient, where possible, to make direct use of the original electricity rather than go through the hydrogen stage. So, a battery-driven EV should be more efficient and desirable than a fuel cell EV.

Efficiencies may well have improved since Bossel's work. The EV market seems already to be reflecting the position he took. The fundamental fact of energy losses in all Green hydrogen applications must always be kept in mind.

As for hydrogen replacing all or most of the world's natural gas, none of the above is cause for optimism. It will be interesting to see if the new Australian R&D effort changes that perception.