Read time: 5 mins
Hydrogen is expected to play a substantial role in the global decarbonisation transition over the coming decades, particularly in hard-to-abate industries such as aviation and freight, and chemical, metal, and cement manufacturing. ‘Green’ hydrogen – produced from renewable energy sources – is currently much more expensive than hydrogen produced from fossil fuels but is receiving major research interest and investment. New ANU research reveals that the models commonly used to estimate green hydrogen production are neglecting an important variable, potentially leading to a significant overestimation in hydrogen production and, thereby, financial viability.
Read time: 5 mins
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Some 96 per cent of global hydrogen production uses fossil fuels, and only 1 per cent is produced from renewable energy through water electrolysis (known as ‘green hydrogen’).
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With green hydrogen production set to play a role in the transition to zero emissions, accurate modelling is critical to establishing how much green hydrogen will be produced by planned infrastructure, which is fundamental to investment cases and environmental impacts.
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ANU research shows that assumptions in the current models can overestimate green hydrogen production by as much as 24 per cent.
With the urgent need to reduce humanity’s reliance on fossil fuels and decarbonise, green hydrogen production is expected to increase. Australia is well placed to be part of this new industry.
As part of these efforts, accurate modelling is critical to establishing the expected hydrogen production of proposed production facilities.
New research from ANU shows that the current models may not be accurate, because they commonly neglect to account for a critical variable in hydrogen production – electrolyser efficiency.
First, a quick primer.
Green hydrogen is produced by using renewable electricity to split water into hydrogen and oxygen. This process takes place in an electrolyser.
Most of the modelling on green hydrogen production simplifies calculations by assuming fixed, high efficiency electrolysers.
But that might be leading to inaccurate results.
In real life, the efficiency of hydrogen production from electrolysers varies with the amount of power provided – similarly to the variable efficiency of a car engine. And green hydrogen is being produced with energy from solar and wind farms, which produce energy variably across a day.
The study, published by experts in the ANU Battery Storage Grid and Integration Program, analysed data from three solar farms and three wind farms in Australia.
The research reveals that with electrolyser efficiency unaccounted for, models could be overestimating hydrogen production by between 5 and 24 per cent.
Overestimating production quantity is equivalent to underestimating production costs: financially, as well as environmentally and in terms of the supporting electricity system infrastructure.
This overestimation has potential spillover effects for policymakers.
Policymakers rely on their accuracy to make informed decisions about the feasibility of projects, and to guide the design of energy policies.
As the green hydrogen industry grows, continuing to overlook this effect could lead to much larger overestimation of hydrogen production, creating problems for regulators and potentially misleading policymakers making important decisions.
“As the green hydrogen industry grows, continuing to neglect this effect would lead to overestimation of expected hydrogen production by tens of millions of tonnes per year.”
