Carbon Capture Storage is an umbrella term that describes many different techniques to trap the gas and prevent its release into the atmosphere. In some cases, CCS involves extraction directly from the atmosphere itself. The environmental benefits seem obvious, as does the potential for a burgeoning new tech industry in its service. Despite its undeniable potential, however, interest in CCS has been waning. Surprisingly, some of the technology’s most vocal detractors are the world’s biggest environmental organisations.
How CCS Works
Used as early as the 1920s to separate carbon dioxide from saleable methane gas, the technology was further refined in the 1970s to help boost oil recovery by pumping byproduct CO2 from nearby facilities back into the ground to displace crude. The process, known as Enhanced Oil Recovery or EOR, remains in use today.
According to the Global CCS Institute’s figures for 2018, of the 18 integrated CCS facilities that are deemed “large-scale” 14 are used for EOR.
The CCS process involves three steps: capturing, transporting and storing the gas. The first step is achieved either in the pre-combustion or post-combustion stages, sometimes with a process known as oxyfuel combustion, which produces a highly concentrated carbon stream for easier extraction. The CO2 is then transported using the same infrastructure that serves the fossil fuel industry. When it arrives at its destination, it is pressurised and stored in its liquid form. Depleted oil reserves and deep saline aquifer formations are the most widely used for storage.
While CCS companies work to improve the operations chain, the scientific community is innovating radical new technologies. Nanoporous materials called metal-organic frameworks, carbon trapping nanosponges and even crystals with highly absorbent pores could be deployed in the near future, boosting the efficacy of the carbon capture process.
Some are hoping to take the process one step further, eliminating the need for storage by upcycling the gas. Research teams at Southern California’s Loker Hydrocarbon Research Institute as well as Bangalore’s Jawaharlal Nehru Centre for Advanced Scientific Research hope to convert CO2 into methanol, a product with numerous industrial applications that can even be used as fuel.
A Contested Cycle
A technique to remove pollutants which are then used to create more pollutants is an environmental paradox that has not been lost on groups like Greenpeace. In 2008, Greenpeace raised the issue:
“CCS is being used as a justification to keep building inefficient, poorly constructed coal-fired power stations – the dirtiest possible way of producing electricity ever invented.”
Greenpeace and other critics argue that CCS encourages an endless cycle that simply needs to end.
Uncharacteristically, energy companies generally agree with environmentalists on the untenability of CCS, albeit for a different reason – the high cost currently associated with the process. CCS is energy-intensive, typically requiring power stations to burn 16 per cent more gas to power the carbon capture process. Even if CO2 emissions are reduced, other pollutants like sulphur dioxide, nitrogen oxides and amine solvents will increase. The additional fuel required for CCS also incurs an environmental cost at the source and in transportation.
These concerns, combined with the uncertainties surrounding potential carbon escape after its storage, all contribute to the feeling that CCS is impractical. It seems the only factors that could change this are heavy state subsidies or additional associated revenue streams. Since the Paris Agreement was signed, neither of those scenarios have come to fruition in any meaningful way. In 2015, ten years after the UK government announced a £1 billion CCS power plant design competition, it abandoned the initiative. Geologist Lord Oxburgh summarised the decision in a government-commissioned report:
“There is no serious commercial incentive, and it will stay that way unless the state demonstrates there is a business there.”
Similar outcomes have materialised elsewhere, with the US halting its flagship Kemper coal CCS project, and Norway, a CCS and EOR pioneer, also cutting funding for CCS applications.