Here's the first three headlines that came up when I googled "hydrogen news" on Friday.

"Australian lab turns hydrogen into green energy with secret catalyst."

"Woodside gets $10 million grant from state government for hydrogen refuelling station."

"Queensland 'super-hybrid' green hydrogen project gets indigenous name and support."

The push for hydrogen - led from Europe like so much of the environmentally led restructure of society - began seriously here a few years ago, and the pace has accelerated since a more renewables-friendly Labor government has replaced the Coalition in Canberra.

What appear to be tidal waves of government (read "taxpayer") funding are leading chief financial officers across the corporate world to see if there is some form of hydrogen subsidy they can apply for.

All of it sounds feasible enough, and there is no doubt that some of the world's smartest technical minds are being paid big bucks to commercialise a nascent technology that its boosters claim will revolutionise almost everything.

But what if the claims, the promises, don't add up?

Elsewhere in today's Newcastle Herald, my colleague Matthew Kelly looks at some conflicting messages about the gas turbine "peaker" power station being built on the old Kurri Kurri aluminium smelter site by the federal government's Snowy Hydro.

Labor said before the election that Kurri would run on 30 per cent green hydrogen from the start, while Snowy Hydro has said repeatedly that the equipment can cope with 15 per cent at the most and that any modification plans were years down the track.

So what's going on? Actually, these sorts of arguments - over how much hydrogen, how it's made, and when it arrives - are nowhere near the only technical problems that need overcoming.

As I mentioned yesterday in the first part of this article, Australia's second-richest person, Twiggy Forrest, has used a global cavalcade of photo-ops to promote his hydrogen interests under the Fortescue Future Industries banner.

At the same time, I couldn't help but notice that Gina Rinehart - top of the Australian Financial Review rich list with $34 billion to his $30 billion - seems far less interested in the new miracle fuel.

One of Rinehart's trusted advisers is the iconoclastic geologist Ian Plimer - whose climate change scepticism has made him a woke target par excellence.

I met the prize-winning professor when he ran Newcastle University's geology school in the 1980s. Later on, I watched him become the toast of the scientific world for his aggressive rebuttals of Creationism and the claim that a rocky outcrop on a Turkish mountain was a fossilised Noah's ark.

But Plimer's 2009 book, Heaven and Earth, and others that have followed, including Climate Change Delusion and the Great Electricity Rip-off, have put him at odds with the "consensus view" (not that it bothers him or, I suspect, Ms Rinehart).

Respecting Plimer's undoubted knowledge of materials and minerals, I asked him this week about the hydrogen push. He said: "Hydrogen cannot be mined. It must be made using energy.

"This is why when there was great push for hydrogen in the 1920s it failed. It also failed because, as a small atom, it diffuses through steel and makes steel brittle. "This means that it can't be stored efficiently and safely.

"This is the other reason it failed in the 1920s. I suspect that the push towards hydrogen has nothing to do with energy and everything to do with subsidies."

I'm not sure about the last point. Companies will always look for handouts, and although Plimer disregards climate change, the funding bodies presumably believe in what they are doing.

At least some in government are aware of the problems.

A RenewEconomy article from March last year cites a Council of Australian Governments (COAG) report that says leakage and embrittlement mean existing gas infrastructure is limited to about 10 per cent hydrogen.

The academic authors of the paper say embrittlement is such a "highly complex materials and engineering problem [that] "many aspects still need to be understood before tangible solutions can be proposed".

Wikipedia's "hydrogen economy" page says, high up, that "numerous technical challenges prevent the creation of a large-scale hydrogen economy".

"These include the difficulty of developing long-term storage, pipelines and engine equipment; a relative lack of off-the-shelf engine technology that can currently run safely on hydrogen; safety concerns regarding the high reactivity of hydrogen fuel with oxygen in ambient air; the expense of producing it by electrolysis; and a lack of efficient photochemical water-splitting technology."

Despite these problems, the entry says, the "hydrogen economy is nevertheless slowly developing as a small part of the low-carbon economy".

Hydrogen as H2 is the smallest molecule in existence, 50,000 times smaller than the width of a human hair, and so it cannot be stored in plastic because it penetrates through the walls.

It penetrates many metals as well as steel, and Wikipedia notes hydrogen "embrittlement" in iron, nickel, titanium, cobalt and their alloys, although copper, aluminium and stainless steels are less susceptible. These characteristics mean hydrogen has big handling challenges that other fuels do not.

That's before we consider the energy needs.

Toshiba's Fukushima green hydrogen plant was described as the world's biggest when it opened in 2020. Its 20-megawatt solar array covers some 22 hectares of land, to power electrolysers rated at 10 megawatts, to produce "up to" 1200 cubic metres of hydrogen an hour.

IN OTHER NEWS:

This equates to about 107 kilograms an hour, or 984,186 kilograms, or about 900 tonnes a year.

Bigger plants, including one in Brazil with a claimed output 10 times that of Fukushima's, are either being built or on the drawing board.

But these are tiny amounts, given the world consumes about 35,000 million barrels of oil and 7,700 million tonnes of coal a year.

It's time the embrittlement problem, especially, is debated more publicly, because while ever it remains, hydrogen can surely only have only a limited role to play in cutting our fossil fuel dependence.