By Chris Johansen
The current interest in hydrogen as a clean fuel to replace natural gas is understandable. When hydrogen is combusted it combines with oxygen to produce water as a by-product (good stuff, mostly, but scientists and engineers will have to solve the problem of excess water vapour).
When the methane of natural gas is combusted it produces carbon dioxide as a by-product (very bad stuff, in terms of climate change). However, whether or not hydrogen can be classified as a clean fuel depends upon how it is made – which is colour-coded.
Green hydrogen is produced by splitting water into hydrogen and oxygen in the process of electrolysis; and the energy derived to achieve this comes from “clean” electricity, such as produced by solar or wind power. Thus there are no greenhouse gas (GHG) emissions during the process.
Blue hydrogen is produced using steam to separate hydrogen from the methane in natural gas. This process releases carbon dioxide, which is putatively captured by a carbon capture and storage (CCS) process. However, prior to this steam reforming process there would be inevitable fugitive emissions of methane, a potent GHG.
Grey hydrogen is also extracted from natural gas using steam reforming but without CCS, thus releasing carbon dioxide and other GHGs into the atmosphere.
Brown hydrogen, from brown coal, and black hydrogen, from black coal, are produced via coal gasification. Hydrogen is produced as well as carbon dioxide and other GHGs which are released into the atmosphere.
Presently, the costs of producing green hydrogen exceed (roughly double) those of producing grey, brown or black hydrogen due to the costs of electrolysers and linking them to renewable electricity.
Current costs of production of green and blue hydrogen would be similar due to the high cost of CCS for blue hydrogen and ever cheaper cost of solar energy for green hydrogen. Many entrepreneurs and initiatives are proceeding with plans to develop green hydrogen at scale, like Andrew Forrest of Fortescue Metals.
They are banking on the cost curve of electrolysers to decline, with mass production, in the same manner as that of solar panels has declined. The Chinese Government for one is going gangbusters on mass producing electrolysers.
Although LNG producers in particular see hydrogen as a threat to LNG, they also see it as a way to prolong sales of natural gas.
For example, Woodside proposes to set up a hydrogen producing facility at Kwinana, using (would you have guessed?) their natural gas piped from the Pilbara as feedstock, i.e. grey hydrogen (unless they have a CCS plan to make blue hydrogen – but that would largely bite into profits).
This is obviously a scheme to prolong the life of their natural gas, by claiming that their end product is “clean”, but downplaying the dirty pathway by which it got there. This project needs to be called out for what it is – greenwashing but by feeding in dirty linen.
There were recent news reports of a dedicated hydrogen carrier ship leaving Melbourne, heralding the beginning of Australia’s hydrogen export boom to Asia. But, wait a minute, where did this hydrogen come from? From the gasification of brown coal – hardly clean, but definitely dirty hydrogen.
It has been argued that even if this shipment is dirty hydrogen, it is part of a pilot process of actually shipping hydrogen, an essential step if green hydrogen is to be exported. However, it provides an avenue for export of blue-grey-black-brown hydrogen, to extend the life of fossil fuels.
This shipment was proclaimed as “blue hydrogen”, on the “promise” that carbon dioxide would be captured by CCS. But this didn’t happen and so the promise was changed to buying “offsets” – which are in most cases a rort used to justify further fossil fuel burning.
In conclusion, when traditional fossil fuels companies say they are going green by moving into production of hydrogen as a fuel, take a step back.
Yes, indeed when hydrogen is combusted, its by-product is the benign water molecule, but the actual GHG emissions from the process depend on how hydrogen is made in the first place.
If the hydrogen is derived from natural gas or coal, then its emissions will end up as little different from directly burning those substances.
So any new hydrogen projects need to be questioned in terms of how ‘clean’ (i.e. what colour) it really is!
We can’t allow corporations, like Woodside, to greenwash us with their hyped-up hydrogen projects. They are aimed at appeasing the public’s appetite for action on climate change, whilst enabling their expansion of fossil fuels, such as the monstrous Scarborough gas project.
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There’s no need for new fossil fuel projects!