Carbon capture, utilisation and storage (CCUS) is forcing itself on to the decarbonisation agenda, including in Ireland, where the first stages of scaling up a sector are evident. But the technology is controversial because it is unproven at scale, is currently very costly, and it comes with a substantial risk that, if applied incorrectly with insufficient regulation, it could become a get-out-jail card for the fossil fuel sector.
The UK government’s plan for CCUS by catching carbon dioxide from big industry and pumping it into rocks under the North Sea – “is a fossil fuel-driven boondoggle that will accelerate climate breakdown”, the Guardian’s George Monbiot predicted.
Its allocation of £21.7 billion to build CCUS capability is the biggest commitment by any state in the world and provides an indication of the huge costs involved. The complexities of energy and carbon emissions, however, are such that CCUS is not a simple yes/no option – nor can it be rejected on the basis of current cost or possible environmental damage.
CCUS entails the capture of CO2, generally from large-point sources such power generation or industrial facilities that use either fossil fuels or biomass as fuel.
If not being used on site, captured CO2 is compressed and transported by pipeline, ship, rail or truck to be used in a range of applications, or injected into deep geological formations such as depleted oil and gas reservoirs or saline aquifers.
CCUS can be retrofitted to existing power and industrial plants, such as a municipal incinerator, allowing for their continued operation. It can tackle emissions in hard-to-abate sectors, particularly heavy industries – notably cement, steel or chemicals.
It is also an enabler of least-cost, low-carbon hydrogen production, which can support decarbonisation of other parts of the energy system, such as industry, trucks and ships. CCUS can remove CO2 from the air – direct air capture (DAC) – to balance emissions that are unavoidable or technically difficult to abate.
From the perspective of an overheating planet, possibly the most insidious use of CO2 is in oil production: enhanced oil recovery typically uses steam, chemical or gas injection to extract oil from otherwise depleted or inaccessible reserves.
The broad context is outlined by Prof Marcelle McManus, director of the Centre for Sustainable Energy Systems at the University of Bath: “There is much discussion about CCUS being used to help the continuation of fossil fuels. However, industry needs to decarbonise – and de-fossilise – quickly. We don’t currently have enough renewable electricity to meet our industry and domestic needs, and some industrial processes are very hard to electrify.”
Fossil fuel states such as Saudi Arabia pushed hard to include CCUS at the UN talks, as they see it as a way to continue their lucrative business. But the vast majority of leaders and scientists see an extremely limited role for CCUS
Therefore, as countries scale up renewable infrastructure and provision, CCUS can form part of the transition, she says.
“This does not need to couple us to fossil fuels long-term, because once we stop taking fossil fuel out of the ground we will continue to need carbon for many materials and processes – and we will need a source. CCUS can be coupled with other fuel sources in the future to help build part of a circular economy longer-term.”
McManus adds: “However, we can’t do this in isolation. Demand management should be the first step and although we do need some storage of carbon in order to help reduce the carbon going up into the atmosphere, it is critical that we create the pathways and technologies for a de-fossilised future rather than just continuing to use fossil fuels with CCUS.”
She stresses that we are “in a crisis and need all of the options available to us”.
The long-term prognosis for the planet is such that technology – including unknown solutions under this heading – will be essential to achieving net-zero emissions by mid-century. And because of global heating, with the average temperature rise likely to exceed 1.5 degrees, the world will probably need to achieve “negative emissions” – ie, CO2 removal from the atmosphere.
DAC technologies extract CO2 directly from the atmosphere at any location. Again, the CO2 can be permanently stored in deep geological formations or used for a variety of applications. This is the most expensive application of carbon capture.
CCUS was acknowledged by UN Intergovernmental Panel on Climate Change in its landmark Sixth Assessment Report in 2022 as a solution for climate mitigation, though it “has the highest cost and lowest possible contribution to net emission reduction in both energy and industry sector”. Nevertheless, it meant CCUS forced itself on to the Cop28 agenda in Dubai last year and countries are now including it as “a dependency” to meet their emission targets.
Fossil fuel states such as Saudi Arabia pushed hard to include CCUS at the UN talks, as they see it as a way to continue their lucrative business, with the emissions being trapped and buried. But the vast majority of leaders and scientists see an extremely limited role for CCUS, especially as it does not even trap all emissions.
The idea that it can allow fossil fuel firms to continue anything like business as usual is a “fantasy”, says the boss of the International Energy Agency, Fatih Birol.
Minister for Climate and Energy Eamon Ryan echoed that view at Cop28 but added: “Hands up, and be honest here. We’re going to do carbon capture and storage.” It could be used with incinerators such as the large Covanta plant in Ringsend, Dublin, and in cement manufacture, he noted.
More than 700 projects are at various stages of development across the CCUS value chain which, analysts agree, if fully deployed would remain well below what is required in the net zero scenario.
Sustainable infrastructure leader with Deloitte Stephen Prendiville says in Ireland this has been predominantly at the research and development stage and still focused on possible uses. A significant amount of pilot projects are beginning to happen, with a handful of Irish companies in that space.
But the negatives are obvious, Prendiville says: “It’s not easy to get validated information. It’s expensive.”
The price of carbon at present is too low to incentivise scale up, though that is expected to change.
There is a need to push on and overcome inherent barriers, Prendiville says, because carbon abatement curves show that if people want a modern lifestyle and economy, “they’re going to need those technologies”.
The UK approach, he explains, is to provide a regulated asset base, which is feasible because it has big industrial centres. Ireland, in contrast, does not have such infrastructure. Accordingly, Prendeville expects the UK to be where CCUS technology will be concentrated.
It will take many years to reach commercialisation, he adds, while big questions remain about who pays for it, what the mandate is and how performance is monitored. These are the sort of questions that were asked about green hydrogen development and utilisation in Ireland, he says, and are being answered with a view to pushing on to industrialisation.
There is a risk that the technology issues could be solved but it may take years working out its commercialisation. So, the CCUS conversation has to be had sooner rather than later, including identifying individual technology providers and storage options, such as the Kinsale or Corrib gasfields.
One Irish company, NEG8 Carbon, is farther down the commercialisation route on DAC than most. It started in 2014 as a spin-out from carbon capture research conducted at Trinity College Dublin and University College Dublin, and following investment in 2021, the team started to commercialise the technology.
It is based in Waterford where its labs and development centre are located. It has developed Ireland’s first operational DAC system, which focuses on an innovative approach to deployment of sorbents to absorb CO2.
NEG8 Carbon says the key to the widespread adoption of DAC technology is the cost per tonne of CO₂ captured and its technology breakthrough allows it to drive down cost.
Its system has been shown to reduce energy consumption by 20 per cent. It reduces the required amount of sorbent by 80 per cent, cuts regeneration time by 90 per cent – which means a much more efficient system – and increases CO₂ uptake by 50 per cent.
It recently announced significant technology upgrades to its DAC system to improve its efficiency. It works by drawing in large quantities of air and passing them over sorbent materials, designed to attract and hold CO2 molecules. Captured CO2 can then be safely stored underground or turned into climate-neutral carbon products, such as sustainable aviation fuel.
“These innovations are making significant improvements to our DAC technology. They enhance both efficiency and sustainability, reinforcing our dedication to providing effective solutions in the fight against climate change,” says Dr John Breen, chief technology officer of NEG8 Carbon.
NEG8 Carbon says its mission to capture 100 million tonnes of CO₂ annually by 2050.
