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Ireland should consider small nuclear reactors to achieve zero-carbon energy by 2050, engineers’ think tank urges

Small modular nuclear reactors may prove to be viable, cost-effective and necessary if economy is to decarbonise, Irish Academy of Engineering report finds

The engine room at the Bugey nuclear power plant in eastern France. Photograph: Emmanuel Dunand/AFP via Getty Images

Ireland should prepare for the possibility of using small modular nuclear reactors (SMRs) to achieve a zero-carbon energy system, which is a key part of decarbonising the Irish economy by 2050, according to the Irish Academy of Engineering (IAE).

Building nuclear capacity must be considered in case options currently being pursued – massive scale up of wind and solar energy with green hydrogen as a backup – “are ultimately unsuccessful or prove not to be viable”, according to a report from the all-island think tank published on Monday.

Nuclear power plants are prohibited under Irish legislation. A nuclear plant was proposed for Carnsore Point, Co Wexford, after the 1973 energy crisis but the idea was abandoned in 1981 following significant protests.

The IAE says circumstances have changed since but State agencies do not have sufficient expertise should this option become necessary. Know-how in the ESB, Environmental Protection Agency, EirGrid and the Commission for the Regulation of Utilities is needed to facilitate “an active fact-based public discussion on these important issues”.


Decarbonising the electricity sector by 2050 by increasing renewables tenfold will inevitably add to consumer costs due to intermittency issues and “can only succeed if there is a secure backup when renewables are not sufficiently available”, the report warns.

Wind speeds vary widely and, at times, wind outputs can drop close to zero, sometimes for days or even weeks at a time. Today, renewables are backed up by fossil fuels, mostly natural gas.

Many countries are proposing SMRs alongside renewables to provide a secure zero-carbon electricity option. They are much cheaper than traditional nuclear plants and designed to be built in a factory, shipped to operational sites for installation and used to generate power or heat. They are also used to power ships and submarines.

Nuclear reactors have been used for power generation for more than 70 years while nuclear power provided nearly a quarter of electricity generated in the European Union last year, with almost no carbon emissions.

“We believe Ireland needs to keep an open mind about the possibility of including SMRs in Ireland’s future energy mix,” said Eamonn O’Reilly, chair of the IAE energy and climate action committee.

“However, passive acceptance that SMRs might be needed is not sufficient, and an active response is required to ensure that, if SMRs prove to be economic, safe and reliable by the mid-2030s, the country has the institutional capacity and expertise that would be needed to introduce them.”

If hydrogen proves unviable or too costly, there is no planned alternative; “far too many eggs are in the unproven basket”, he said.

“If we wait until SMRs are proven elsewhere to begin to develop this institutional capacity, it will be too late and it might not be possible to decarbonise the energy sector by 2050. Preparing for the possible introduction of SMRs needs to start today to create an option that might be required in the 26 years from now to 2050,” he added.

At a Nuclear Energy Summit recently, 32 countries committed to include nuclear power in a global effort “to reduce greenhouse gas emissions from both power and industrial sectors, ensure energy security, enhance energy resilience and promote long-term sustainable development and clean energy transition”. Nuclear power was also adopted at COP28 climate summit last year as “one of the pathways to decarbonise energy”.

SMRs under development are an emerging option based on both tried and tested reactor types and on newer advanced technologies, said Mr O’Reilly, a former chief executive of Dublin Port. “If SMRs prove to be viable, they will likely be deployed in large numbers within 10 to 15 years. This could happen, most relevantly from Ireland’s perspective, in the UK.”

Ireland’s island location, with exposed energy supply chains, creates particular challenges to achieve a zero-carbon energy sector while guaranteeing reliability and security of supply, Mr O’Reilly said.

The IAE believes a response similar to the second oil shock of the 1970s is needed with institutional capacity developed as a matter of policy in State bodies, which should engage with SMR manufacturers to evaluate their potential with the realistic prospect that Government policy could change to allow them to be deployed if merited, Mr O’Reilly said.

The UK is in a process of selecting the best SMR design from six prototypes. France recently committed €300 million through the nuclear generating company EDF to advance SMR options while Terrapower in the US founded by Bill Gates is due to begin construction of its Natrium-branded SMR this month, which is cooled with liquid sodium rather than water. The global race to develop SMRs is led by China, Russia and the US.

Appropriate energy market structures for Ireland – in consultation with SMR manufacturers and project developers – will be needed based on experience in other countries – to enable the introduction of SMRs, alongside renewables, into Ireland’s energy mix, the IAE recommends.

The Government also needs to develop the necessary resources to be able to assess the environmental impact of proposed SMR developments and license and regulate them.

“It is only if these steps are taken that there can be an informed national discussion on the possible introduction of SMRs into Ireland’s energy mix and important issues – including safety and nuclear waste – can be meaningfully debated,” Mr O’Reilly said.

If other better ways to achieve zero carbon energy without SMRs were found, that preparatory work could be ended.

Many of the justifications for not using nuclear power no longer apply, the IAE says, such as “the idea that Ireland is too small for nuclear”.

“One of the reasons that a nuclear plant wasn’t constructed then was its large capacity compared to the size of the Irish grid. At that time, a single nuclear reactor (500 megawatts) would have had a capacity equivalent to 25 per cent of maximum national demand (2,000MW).”

In contrast, SMRs under development today have power capacities lower than that of an average large generating unit. Typically, they have a power capacity of 300MW or less, which is about a third of standard plants.

The potential of SMRs has been downplayed at a policy level on the basis of a lack of nuclear expertise in Ireland, the IAE notes. “We didn’t have the expertise to build Ardnacrusha in the 1920s but did so nonetheless. There was no previous experience of building offshore wind farms when Airtricity decided to develop the 25MW Arklow project 20 years ago. We have no established expertise in hydrogen, yet it is central to Government policy. Developing institutional capacity now will ensure that Ireland would have the required expertise in SMRs if it is ultimately needed.”

Unlike SMRs – which can provide firm and dispatchable power – renewables require backup zero-carbon generation capacity. Analysis on the likely price of hydrogen.

“This is a significant additional cost which the consumer ultimately bears,” the report says. “In addition, SMRs provide services to the grid (to maintain stability) which renewables cannot do. In a grid approaching 100 per cent renewables, these services will have to be purchased from other sources with the cost, again, passed on to consumers.”

The SMR option might not be too expensive, when all costs of the energy transition are known, the IAE found.

On issues of safety, nuclear waste and public opinion, it says: “The environmental and big crash concerns many people have with nuclear energy will need to be considered against the impacts of climate change. They will also have to be assessed alongside the environmental and other risks which backup zero-carbon generation technologies – such as hydrogen or ammonia – could pose.”

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times