The Government’s National Hydrogen Strategy envisages green hydrogen playing an important role as a zero-emission alternative to fossil fuels in generating electricity when renewables aren’t available; in long-duration renewable energy storage; in decarbonising industrial processes; and as a transport fuel in sectors such as heavy goods, maritime and aviation. It also explores the potential for Ireland to become an exporter of green hydrogen.
For these lofty ambitions to be realised, however, Ireland first needs to produce ample supplies of the gas. That is easier said than done, given that we are starting from a zero base.
At present, hydrogen is typically manufactured using a process known as steam-methane reforming. This uses natural gas as the base material and generates unhelpful byproducts. This is known as grey hydrogen. When carbon capture and storage is added it is known as blue hydrogen. Further along the colour spectrum is black hydrogen, which is produced from coal or lignite through a gasification process that produces even more undesirable byproducts.
Green hydrogen is created from electrolysis, using renewable electricity. Electrolysis is the process of using an electric current to split water into hydrogen and oxygen, and when the electricity comes from renewable sources there are no nasty byproducts.
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Ireland’s ambition for green hydrogen is based on the premise that when offshore wind gets up and running at scale there will be times when excess electricity is being produced and, rather than dumping or curtailing it, it would be used to power electrolysers to make green hydrogen.
But this may not be as straightforward as many seem to assume. Deloitte sustainable infrastructure leader Stephen Prendiville says many of the projections made for green hydrogen are based on the assumption that the electricity used to create it comes at zero cost. Noting that black hydrogen can currently be produced at less than €2 per kg, he points out that if the capital cost of the offshore wind or solar farm used to produce the green equivalent had to be accommodated, the production cost would be between €4 and €5 per kg.
“The challenge in thinking about the green hydrogen opportunity in terms of using curtailed energy at zero cost is that it doesn’t help you get the offshore wind up and running,” he explains. “You therefore need a primary use for offshore wind and if that is not green hydrogen the Government and the regulators will have to create a guaranteed price for that power to get the projects moving.”
Prendiville believes the ambition for Ireland to become an exporter of hydrogen may need to be rethought in the face of economic realities.
“Green hydrogen absolutely has a role to play in our decarbonisation trajectory but it is not free,” he says. “It is not this miracle solution to our future needs.
“If Ireland is to export green hydrogen, it will be competing on a commodity market. If Ireland is producing green hydrogen for export, we can’t be dependent on excess power because we will have contractual obligations to customers. The opportunity cost will not always be zero, it will be somewhere between €5 and zero. And we will have to compete with countries that can produce it cheaper than we can.”
Security of energy supply is currently the best case for green hydrogen production in Ireland, in Prendiville’s estimation.
“That’s the only reason to think about it; otherwise we could just import it,” he says. “We can export the hydrogen if our storage capacity is full. That’s a completely different model than export first.”
Regardless of where the green hydrogen will come from, Gas Networks Ireland is preparing for it.
“We have been undertaking preparations for the onboarding and transportation of hydrogen on the network for a number of years” says Brian Mullins, hydrogen innovation director with the organisation. “This is against the backdrop of a National Hydrogen Strategy which includes a proposal to repurpose gas pipelines to transport hydrogen between areas of production and demand areas.”
A dedicated hydrogen programme team has been set up to lead the necessary preparations.
“Our focus at present is on undertaking comprehensive testing of our pipelines and general network assets to confirm compatibility with hydrogen,” says Mullins. “We are working with a number of external parties on this, including academia, engineering specialists and other peer pipeline operators across Europe. This testing regime is part of a comprehensive review process to ensure that the network is ready for hydrogen when it comes on-board and to provide the necessary reassurance that hydrogen can be safely transported on the gas network.”
The long-term plan is for a combination of biomethane and green hydrogen to eventually replace natural gas on the network and Mullins believes the primary source for both will be domestic production.
“Hydrogen in Ireland is likely to come from a mixture of imports through interconnectors and domestic production via renewable energy sources,” he says. “The longer-term plan to convert the existing gas interconnectors to transport hydrogen could provide an opportunity to both import and export hydrogen with Great Britain and interconnected European markets to take advantage of price signals, akin to what we see in the existing electricity interconnectors between the two jurisdictions.
“However, the baseline assumption would be that against the scale of offshore wind planned for Ireland, the primary source of hydrogen in Ireland would be indigenous green hydrogen from excess renewable energy sources.”