With carbon capture, utilisation, and storage (CCUS) vital to net zero ambitions, Scotland has notable advantages in developing this key industry.

Many of the nation’s depleted subsea fields are ideal for the underground storage of captured carbon. Alongside this, Scottish expertise in the oil and gas sector provides the necessary infrastructure and skilled workforce to expand CCUS capabilities.  

The pathway to net zero 

According to Stuart Haszeldine, director of Scottish Carbon Capture and Storage (SCCS), and professor of carbon capture and storage at the University of Edinburgh, the chance of reaching net zero without carbon capture is “less than zero”.

“In any of the evaluations done recently – whether it’s the Intergovernmental Panel on Climate Change, the International Energy Agency or even the UK committee on climate change – all say we’ve delayed taking action on CO2 for so long that to make net zero happen in the mid-century, CO2 capture and storage is essential,” says Haszeldine.

“Not just CO2 capture and storage by decreasing emissions, but removing emissions that have already been emitted. commonly known as greenhouse gas recovery, through direct-air capture or bioenergy with CCUS.”

Infrastructure and geology for CCUS

One of the most effective methods of storing CO2 is to inject it into old oil and gas fields that have the required geological conditions.

However, CO2 can expand like an aerosol when injected into low-pressure fields. As a result, CO2 may freeze the water in the field. This stops further gas injection and delays the start of potential CO2 storage projects until frozen water melts. 

The Acorn CCS site avoids this issue and provides excellent conditions for carbon capture. The project, integral to Scotland's CCUS cluster, is being driven by a partnership between lead developer Storegga, technical developer Shell UK, Harbour Energy, and North Sea Midstream Partners.

The project is expected to transfer and permanently store CO2 in areas 2.5 kilometres below the seabed, 100 kilometres off the coast of St Fergus.

Up to a third of UK gas enters the country at St Fergus Gas Terminal on the Scottish coast. Located nearby, Acorn CCS has the capacity to store up to ten million tonnes of CO2 per year by 2030.

“The advantages of Acorn CCS are that it can reuse existing equipment and pipelines going offshore to a well-understood geological storage site for the carbon dioxide, which is easy  to develop and relatively well-known,” Haszeldine says.

“We’re dealing with known types of equipment — known pipelines, known geology, and offshore contractors who are well established and able to build the equipment by transferring expertise from the oil and gas experience of the UK.”

Economic benefits of carbon capture

The Acorn project has access to established oil and gas infrastructure. Combined with a detailed understanding of subsea storage, this provides opportunities to save costs with relatively few adaptations for CCUS.

“Reusing pipelines can save you hundreds of millions of dollars. Reusing the geological evaluations that have been done for oil and gas, exploration and production can save you ten years,” says Haszeldine.
Carbon storage sites will be in high demand throughout Europe in the coming decade. This could make captured CO2 a significant source of revenue for the Scottish economy.

“We know from the work that has been done by Acorn – and the work by the Norwegian Northern Lights project – that there is a huge demand for takeaway of CO2 from all industries in all coastal European community members, ranging from Norway, Sweden, Finland, Denmark, the Netherlands, Belgium and France to even Germany, because of access to the sea down the river Rhine,” adds Haszeldine. “There’s a demand of about 20 times more than the available storage services at the moment.”

Blue hydrogen: a viable interim solution 

During the recent global energy crisis, hydrogen has attracted significant attention as an energy vector. One of the main reasons for this is that the gas creates zero emissions at the point of use and may be used as a fuel in various applications.

However, hydrogen can’t be used as an exact replacement for all fossil fuel uses. “In the end, the market will decide the best industrial applications for hydrogen and the need for batteries in the heavy haulage sector,” says George Tilley, hydrogen opportunity manager at Scottish company Storegga, which is driving advances in the development of carbon capture, storage, and hydrogen solutions, including Acorn CCS.

“The hotter the temperature, the more direct the heat, the better the thermodynamic offering of hydrogen. We need to get to net zero. We need carbon capture to scale hydrogen to reduce dependency on fossil fuels,” he adds.

The most common techniques to meet current global hydrogen needs are steam reforming of methane (grey hydrogen) or gasification of coal (brown hydrogen). However, in the absence of carbon capture, these processes are estimated to emit 800 million tonnes of CO2 per year,  equivalent to the annual carbon emissions of Germany.

According to Scotland’s Hydrogen Policy Statement, a hydrogen economy can be built by transitioning from the blue hydrogen initiatives of the 2020s to large-scale green hydrogen production by 2045.
Green hydrogen is created by splitting water into its chemical elements using electrolysers powered by renewable energy. Storegga is actively involved in initiatives that will use this method of production. However, the technology is not yet scalable or ready for supply chain integration.

In the interim, low-carbon — or ‘blue’ —hydrogen is a practical stopgap. It’s produced using the same process as grey hydrogen, but the resulting CO2 emissions are captured for use in other processes or stored underground.

Scotland's hydrogen economy

Scotland has a sizeable advantage in green energy due to the crossover between its oil and gas industry and fledgling CCUS and hydrogen sectors. There’s also crucial financial support from the Scottish Government.

Tilley believes the role of Scotland’s North Sea oil and gas industry is fundamental to the energy transition.

“There are many, many people and companies in Scotland who have been operating for some of the last 50 to 60 years since gas was first discovered and commercialised in the North Sea,” he says. “The Scottish heritage and the Scottish workforce are a key source of competitive advantage for the UK compared to other countries, which don’t have an offshore energy industry. Their skills are transferrable

Growth in CCUS and hydrogen production is key to reaching Scotland’s ambition of five gigawatts of installed hydrogen production capacity by 2030. By 2045, this target rises to 25 gigawatts. Several projects are already underway to achieve this increase at scale.

The team behind the Acorn CCS initiative is developing a specialist facility to collect natural gas from the North Sea and convert it into low-carbon hydrogen. CO2 emissions from the processes would be stored via Acorn CCS.

With CCUS an essential solution for decarbonisation, Storegga is set to play an important role in the global energy transition. Storegga’s predecessor, Pale Blue Dot, has been at the heart of the energy industry’s decarbonisation since 2007. Storegga is now positioned to continue this legacy and help establish Scotland as a world leader in CCUS.

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