Features Australia

Twiggy’s fugitive gas

Hydrogen is the new black

6 November 2021

9:00 AM

6 November 2021

9:00 AM

Renewables are so yesterday. It’s now all about hydrogen. But not just any hydrogen – it has to be green hydrogen.

Billionaire and iron ore magnate, Twiggy Forrest, has even gone to the trouble of advertising green hydrogen on cabs in London and Glasgow to coincide with the COP26 climate conflab in Glasgow which commenced this week.

To be sure, the virtues of hydrogen have been known for a very long time, although so have the pitfalls. The ancient Egyptians had a crack at extracting hydrogen from water in anticipation of the energy that would be released. The blimp operators were also keen on hydrogen until the Hindenburg airship exploded while flying over New Jersey in 1937.

Weirdly, President George W. Bush was a big fan of hydrogen and committed over $2 billion of government funds to research and develop hydrogen as a source of energy. He predicted that we would all be driving around in hydrogen-powered cars by 2020. Unsurprisingly, the money was spent but there was very little to show for it.

It should be pointed out here that hydrogen has been extracted and used for particular purposes for many decades. It’s vital for oil refining, for instance, and is used to extract sulphur from natural gas. It’s an excellent reactant.

But virtually all the hydrogen currently used is brown – that’s right, hydrogen is colour-coded. It is extracted from the gasification of coal and the CO2 emissions are released into the atmosphere. For climate activists, this is bad, very bad.

The hope of the side is green hydrogen which, in theory, can provide a source of energy which can generate electricity as well as fuel vehicles and heat buildings. Green hydrogen is derived from the electrolysis of water using renewable energy. Bear in mind here that the water has to be as pure as possible and purification takes energy.

There is also blue hydrogen which is generated from natural gas (methane) and the CO2 emissions are captured and stored. There is quite a barney going on between the advocates of green and blue hydrogen.

There are several fundamental problems with hydrogen not least that it that takes energy, a lot of it, to extract it from other compounds. And there’s no getting around the second law of thermodynamics which states that ‘in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state’. In other words, there will be less energy out than energy in.

It also takes more energy to separate hydrogen from water than it does to separate hydrogen from methane. It’s why, at this point, green hydrogen is much more expensive than blue hydrogen. A common target for green hydrogen is for the cost of extraction to get below $US2 per kilogram if there is any chance it can compete with other energy sources. At this point, no potential producer of green hydrogen is close to that figure.

But separating the hydrogen does not end the problems of hydrogen as a fuel source. It has to be transported and, as a very light element, it is prone to leak through pipelines. It is also potentially flammable and prone to explode. While these issues can be dealt with, it is expensive to do so.

One of my old mates, who is a trained industrial chemist, relates this telling tale about the perils of transporting hydrogen. ‘It’s a lesson I learnt when I was working very early in my career on a large ICI petrochemical site at Teeside in the north east of the United Kingdom. I was involved on a plant producing polypropylene which was about 750 metres away from a large ethylene cracker. The manufacture of polypropylene requires small quantities of hydrogen, and the cracker had a surplus of hydrogen as a by-product.’

‘During my time there, we needed to install a new hydrogen pipeline between our plant and the cracker. The old engineer I worked with designed this pipe with a pressure rating about five times that required, and insisted that the pipe had virtually no flanges, and that all the welds had to be to a very high standard.’

‘I remember thinking, and then saying, that this seemed like a ridiculously conservative and very expensive approach. The old time Yorkshire engineer smiled at me and said: “Well laddie, they probably didn’t tell you this at university in Australia, but hydrogen is the most fugitive gas around”. We pressure tested the pipeline when it had been completed, with water up to the design pressure – absolutely no pressure reduction, over about five days. We then put hydrogen into the pipeline at the normal operating pressure and left it over a weekend.’

‘When we returned on the Monday, there was virtually no pressure left. Many X-Rays were then taken of the welds on the pipeline – one weld was found to have small micro porosity defects, which obviously weren’t porous to water at five times the pressure, but through which hydrogen had leaked at a fair rate.’

The point of this long quote is that it’s easy to downplay the technical difficulties associated with hydrogen, but veteran wise-heads have experienced the problems in practice. There are doubtless solutions, but most of them are very costly – using ammonia to transport the hydrogen, for instance. There is also a fundamental problem that, for electrolysis to be an economical option, the diodes need to operate 24/7 but renewable energy alone can provide only intermittent energy.

It’s not entirely surprising that Forrest has branched out from the production of iron ore sold solely to the Chinese; the business is like a one-trick pony and China’s steel production is responsible for 6 per cent of the world’s emissions. It makes sense to diversify into other areas, not least to mitigate risk.

But let’s not get too worked up about green hydrogen even if various state premiers are tripping over themselves to offer up taxpayers’ money to support Forrest’s endeavours. (Dominic Perrottet should know better, although he is using taxpayers’ funds to set up a government-run hedge fund.) All that talk of Australia becoming a hydrogen superpower is premature, to say the least.

But the rhetorical value of hydrogen should not be underestimated. Whenever anyone murmurs reservations about the intermittency and unreliability of solar and wind power, the response will generally contain the word ‘hydrogen’. It’s meant to keep the true believers believing.

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