Carbon capture and storage (CCS) technologies can effectively lower greenhouse gas (CO2) emissions from power plants and industrial facilities by collecting this CO2 from exhausts and permanently depositing it underground in geological formations similar to oil or natural gas reservoirs.
CCS technology can also be applied to certain forms of renewable energy sources – this process is known as bioenergy with carbon capture and storage (BECCS).
What is CCS?
Carbon Capture and Storage (CCS) refers to an umbrella term covering several technologies that can significantly lower climate-warming CO2 emissions from power generation and industrial processes, such as steel or cement production. CCS involves collecting CO2 at its source before transporting and permanently storing it underground.
CCS can also be used to “decarbonize” industries that cannot easily switch over to renewables, like heavy industry or the oil and gas sector. CO2 from these sectors can be captured at refineries before being stored underground in deep geological formations that have been used as oil reservoirs for millions of years – something CCS provides.
However, CCS alone will not ensure humanity keeps global warming to 1.5degC or lower. CCS should form part of a portfolio of mitigation options alongside renewables and the ban on fossil fuel subsidies; currently however it is being developed by fossil fuel industries with public subsidies and tax credits being provided as financial support.
How does CCS work?
Process involves collecting CO2 at its source – such as power plants and industrial processes – before storing it underground to prevent further release into the atmosphere.
Capturing CO2 emissions involves three main approaches: post-combustion, which extracts carbon from flue gases after fossil fuel combustion; pre-combustion, which removes CO2 before combustion in gasification or oxy-fuel processes; or scrubbing which chemically removes emissions at their source. Once captured, CO2 can then be compressed and stored safely in deep geological formations like depleted oil and gas reservoirs or saline aquifers with long-term stewardship essential to ensure safety and reliability.
Captured CO2 can also be converted to hydrogen through electrolysis, providing industry and transport with access to clean energy without the need to upgrade their equipment at once. This gradual transition towards renewables allows industry and transport to transition while still providing back-up energy sources to prevent blackouts or power shortages.
What are the benefits of CCS?
Carbon capture and storage technology is one of the key solutions available for mitigating global CO2 emissions. By capturing and storing CO2, we can minimize how much of it is released when burning fossil fuels such as coal, oil, or natural gas or when running industrial processes such as cement and steel making processes.
CCS technology also helps decarbonise hard-to-decarbonise sectors such as heavy industry and power plants, enabling them to continue operating while dramatically cutting their carbon emissions. CCS can even enable negative emissions by pairing it with bioenergy, waste-to-energy or direct air capture technologies which remove more CO2 than they produce from the atmosphere.
Once captured, CO2 is safely injected underground in geological formations like saline aquifers or depleted oil and gas reservoirs for permanent isolation. Regulator frameworks exist worldwide that regulate geological CO2 storage; one such framework is London Protocol (LP), providing legal grounds to allow for the safe injection of CO2 into subseabed geological formations for isolation purposes.
What are the challenges of CCS?
Carbon capture and storage (CCS) is an essential technology to reaching net zero industrial emissions, yet significant challenges remain. CCS costs more than other sources; for example adding CCS to a coal power plant raises energy costs by approximately 25% due to additional energy requirements needed to run its CCS system.
CCS presents several technical challenges on its path towards commercial scale, such as improving CO2 capture processes and lowering project costs. Chemical and petroleum engineers play a vital role in these efforts by contributing expertise such as subsurface engineering, reservoir characterization, injection techniques and project management.
Limiting factors include geological storage sites. According to estimates by the IPCC, up to 10 gigatonnes of CO2 could be stored underground through used oil and gas wells by 2050; this will require massive deployment efforts. Policies focused on carbon pricing, public investment, subsidies or clean energy standards that credit companies for using CCS could help drive adoption rates forward.