What is carbon capture and how can it help fight climate change?

Photo courtesy of Carbon Management Canada

As countries around the world explore ways to combat climate change, one method that is seen as having potential is carbon capture, utilization and storage (CCUS). As the name suggests, CCUS is a technology that captures CO₂ from industrial emitters in sectors such as oil and gas, cement, fertilizer, steel and power generation before it is released into the air. The CO₂ is then either stored deep underground or used for other purposes, such as other industrial processes, or in cement and other consumer products.

“CCUS is one of the tools for Canada to achieve its emissions reductions targets and to assist in the decarbonizing of high emitting sectors,” says Dr. Don Lawton, Vice President of Research and Operations at Carbon Management Canada (CMC).

Carbon management is an important tool to tackle climate change and support decarbonization, according to Natural Resources Canada.

Carbon Management Canada is a not-for-profit organization working to develop and deploy emissions-reduction solutions and support Canadian industry in their net-zero carbon programs. Scotiabank has partnered with the organization on its carbonNEXT initiative, which provides funding to help drive the development and scaling of Canadian CCUS ventures and technologies.

What exactly is carbon capture, utilization and storage?   

CCUS technologies aim to remove or reduce CO₂ emissions by capturing them from high-emitting sources such as steel plants. In some cases, the CO₂ can be used on location for industrial processes or for manufacturing value-added products. For example, captured carbon dioxide can be used in concrete making, reducing the amount of water and energy needed in the curing process. Alternatively, it can be used to produce chemicals such as ammonia for fertilizers, or carbon fibre for industrial applications.

If utilizing CO₂ is not possible at the location of high emissions, then it can be compressed into liquid for transportation by pipeline, truck or ship to a location where it can be utilized or stored more than a kilometre underground in porous rock formations that hold saline water.  

“The Western Canada Sedimentary Basin has enormous potential to store many gigatonnes of CO₂,” Lawton said.

Globally, an estimated 2,000 to 10,000 million metric tonnes of CO₂ will need to be captured annually to reach net-zero, according to Foresight Canada. But the CCUS technologies needed to achieve this goal are expensive and may make that goal unrealistic, according to a recent Scotiabank Economics report on carbon capture by economist John McNally. 

How is carbon captured?

There are currently three principal ways to capture carbon from emission point sources: pre-combustion carbon capture, post-combustion carbon capture and oxy-fuel combustion systems. 

Pre-combustion carbon capture technology captures the CO₂ from fossil fuels before they are burned, making it a preferred method for reducing emissions from power generation or industrial processes. Through various chemical processes, carbon dioxide is more easily captured for storage or utilization.

Pre-combustion (when applicable) can also be more energy efficient per tonne since it captures nearly pure CO₂, whereas post-combustion the CO₂ becomes diluted with other gases requiring costly separation and purification processes. Pre-combustion capture is beneficial for production of syngas, a mixture of predominantly hydrogen and carbon monoxide, that can be used in valuable chemicals and fuels like hydrogen for fuel cells.  

Post-combustion carbon capture involves capturing carbon dioxide emissions from the exhaust gases of industrial processes or power plants after combustion has occurred. Flue gas, being a mixture of gases, requires separation to isolate the CO₂ before capture processes can be applied. 

In Canada, the post-combustion method is used at Boundary Dam, which started operations in 2014, in Saskatchewan. 

(Another category is carbon dioxide removal (CDR) directly from the atmosphere. It captures CO₂ directly from the atmosphere independent of any point-source emissions.)

How is carbon dioxide stored once captured?

Carbon dioxide can be stored in various ways, including in seawater and soils. A common way to store captured carbon dioxide is in the ground, a method called geological sequestration, which involves injecting carbon dioxide into deep underground geological formations – typically at depths of more than one kilometre. A common type of storage reservoirs are saltwater aquifers and depleted oil and gas fields.

The carbon dioxide is injected into those formations via a well or an array of wells and an impermeable cap rock, which acts as a seal, and prevents carbon dioxide from escaping.

What are the drawbacks or obstacles with CCUS? 

CO₂ capture is expensive and more widescale adoption of CCUS at scale will likely require industry incentives. “Significant research is also being undertaken to reduce the cost of capture from emitters and for direct air capture,” Lawton said. For storage, he added that it is important that measurement, monitoring and verification practices are undertaken to ensure permanent and secure storage. 

In its "Net Zero by 2050" report, the International Energy Agency (the IEA) projected that investments of US$160 billion will be needed by 2030 for CCUS technology. The number of announced projects for large-scale technologies has increased significantly in recent years, according to the IEA. If all projects in the pipeline come to fruition, carbon dioxide capture capacity would increase more than eight-fold to nearly 400 million metric tonnes per year in 2030.  Some studies have cast doubt on the efficiency of carbon capture to make any impact with decarbonization. But the technology continues to evolve, and technology developers are looking to use captured CO₂ in a myriad of ways.

“CCUS is not the silver bullet that alone will enable emissions reductions goals to be met,” said Lawton. “It is one of a broad portfolio of technologies needed to reach net-zero emissions by 2050, but it is a technology that can be implemented at large scale by 2030.”

In 2021, Carbon Management Canada and the Foresight Cleantech Accelerator Centre joined forces to establish carbonNEXT, a carbon-tech commercialization hub aimed at accelerating the scale-up and adoption of Canada’s carbon technology companies. Scotiabank is a founding sponsor of carbonNEXT.

“Carbon capture is the most expensive part of the CCUS value chain and it is important that research into new capture technologies is supported,” Lawton said.

What progress has Canada made on CCUS? 

Canada's carbon management strategy, aims to reduce emissions by 40% to 45% below 2005 levels by 2030. 

For context, Canada’s CO₂ emissions in 2022 was 551 megatonnes, representing approximately 78% of this country’s total greenhouse gas emissions.

There are eight operational commercial-scale carbon capture, removal, transport and storage projects in Canada, according to IEA data.

Canada is a world leader in implementing CCUS at broader scales, Lawton said, but more research needs to be undertaken to ensure that Canada’s goals can be met.