Green hydrogen could unlock curtailed Irish wind output

Raymond Shi


Additional reporting by Jake Stones

LONDON (ICIS)–Green hydrogen will play an essential role in Ireland meeting its net zero emissions targets, with the technology able to serve as a key balancing mechanism of the grid while facilitating the decarbonisation of a greater range of sectors.

An analysis authored by Gavid & Doherty Geosolutions on behalf of Wind Energy Ireland published on 19 January outlines that Ireland’s abundance of wind generation has the potential to produce vast quantities of green hydrogen.

Green hydrogen could be produced during periods of high wind output, and subsequently be used to produce electricity during periods of low renewables.

This would enable a smoother matching of energy supply to the daily load profile and ultimately reduce supply risks related to the intermittency of renewable generation.

The report also details how green hydrogen could be developed as a medium for reducing emissions in traditionally harder to reach sectors such as industry and transport.


Ireland’s net-zero targets are ambitious, with its recent Climate Action Plan aiming to achieve a 51% reduction in overall greenhouse gas emissions by 2030, while reaching net-zero emissions by no later than 2050.

In terms of renewable targets, Ireland aims to increase the proportion of its renewable electricity up to 80% by 2030, which is spearheaded by plans to reach 5GW of offshore wind energy by the same deadline.

Onshore wind and solar buildout are supported via the country’s Renewable Electricity Support Scheme (RESS).

At least five RESS auctions are planned to be held up to 2025 to assist towards the government climate targets.

Offshore wind installations will be auctioned under a separate RESS auction, with the government currently undertaking a consultation to develop the appropriate process for its first auction.


According to ICIS Analytics forecasts, annual power generation in Ireland will remain above national demand out to 2050.

As the share of renewable generation in the energy mix rises, this means it will be increasingly difficult to balance the grid, with an excess of supply likely to lead to periods of downward dispatch of wind generation.

To ensure the secure operation of the transmission system, EirGrid sets a limit on the amount of demand that can be met by renewable electricity, known as the System Non-Synchronous Penetration (SNSP). At present, the SNSP limit is set at 75%.

Dispatch down due to overall power system limitations is defined as curtailment, while times when there is insufficient grid capacity to move the energy around is referred to as constraint.

The quantity of both curtailment and constraint in Ireland has increased in recent years in line with greater wind capacity additions.


One potential use of the curtailed renewable power would be to capture it as dispatchable energy via the process of electrolysis.

Curtailed power totalled 734GWh through 2021 based on ICIS calculations using the average curtailment percentage across the first eleven months applied to annual wind data.

This could have produced roughly 514GWh of renewable hydrogen if using a 70% electrolyser efficiency.

Such hydrogen could then be used to balance periods of low renewable output by offering dispatchable, zero-carbon power.

The Keadby Hydrogen plant, due to come online towards the end of the decade, is expected to have a capacity of 900MW, with maximum hydrogen demand of 1,800MW.

Using this metric, hydrogen produced from curtailed wind generation in 2021 would be able to power the Keadby Hydrogen plant for 285 hours over the course of the year.

Large-scale storage would be required for this scenario. However, Ireland’s dCarbonX has outlined plans for a 3TWh hydrogen storage facility offshore of County Cork, Ireland.

Speaking to ICIS about the project, Irish utility ESB said the storage facility could be online by 2026-2027.

“We would base the business case around large scale offshore wind to dedicated hydrogen production, while mopping up any curtailment as required and available – large scale geological storage is critical in this equation,” John O’Sullivan, co-founder of dCarbonX Limited said.

“Ireland plans to have 40-50GW of offshore wind by 2050. With a limited population and industrial base plus a net zero plan, we need to get to hydrogen at large scale to decarbonise plus develop an overseas energy export business which will complement our Irish green electrons.”

ICIS has previously forecast that excess power generation in Ireland could produce 2.3TWh/year of renewable hydrogen.


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