Carbon Capture and Storage (CCUS) technology could dramatically decrease fossil fuel emissions.

CCUS involves three steps: collecting CO2, transporting it and then storing it underground.

Since the 1970s, CCUS technology has been utilized for natural gas processing, ethanol production and enhanced oil recovery purposes. Furthermore, it has also been successfully utilized in coal-fired power generation applications.

Carbon dioxide is a greenhouse gas.

Carbon dioxide (CO2) is one of several greenhouse gases responsible for warming our atmosphere by absorbing and radiating infrared energy into space, heating up Earth. Carbon capture and storage technology aims to prevent additional CO2 from entering the atmosphere by collecting it from fossil fuel power plants and other industrial sources and depositing it underground geologic formations.

CO2 can be collected by isolating it from other pollutants in exhaust from fossil fuel-powered electricity generation plants or from industrial processes like ammonia and ethanol production, then compressing into liquid form for transport via pipelines to storage sites.

Cost of CO2 capture varies across sectors and industries depending on engineering and economic modeling, but typically higher-emitting sectors like electric power generation or some industrial production require greater costs of carbon capture compared to lower emission sectors such as agriculture or transportation. Captured CO2 may either be stored underground geological formations such as old wells for storage purposes; or put to beneficial use such as utilization (carbon capture utilization and storage (CCUS). Geologic storage involves injecting CO2 underground for permanent storage.

Capturing CO2

Carbon Capture and Storage (CCS) refers to capturing CO2 emissions from power plant exhaust streams and permanently storing them underground, as part of clean energy technologies. Although CCS technologies have already shown promise as emissions reducers, more widespread adoption would help make significant emission cuts possible.

CCS is typically employed in industrial processes like natural gas processing, ammonia and ethanol production where CO2 capture costs are significantly less than from power plants. Furthermore, it’s widely employed for enhanced oil recovery (EOR), where CO2 injection into depleted reservoirs improves oil recovery rates.

Scientists at Oak Ridge National Laboratory have developed a way of directly extracting CO2 from air, making CCS an integral component of global climate change mitigation measures. Unfortunately, however, the technology remains costly as it requires significant energy input to compress and cool the high-pressure, low-temperature stream of CO2. Furthermore, large pipelines will likely need to be constructed or maintained for this process to work effectively.

Utilization

Carbon Capture, Utilization, and Storage (CCUS) technologies hold great promise to mitigate carbon dioxide emissions from coal- and gas-fired power plants. CCUS systems divert captured CO2 away from entering the atmosphere to productive use or store it underground in geological formations.

CCUS can be applied to existing industrial facilities such as steel plants and cement factories, or new plants built with carbon capture technology. While they would continue producing CO2, emissions would be drastically reduced and allow these plants to meet climate goals more easily.

Pre-combustion carbon capture technologies transform fuel into syngas, or synthesis gas, which primarily consists of carbon monoxide and hydrogen by passing it through a chemical shift reaction, then using physical solvents to separate CO2 from hydrogen molecules.

Researchers are developing catalysts that can convert carbon dioxide to valuable industrial chemicals such as plastic olefins, methanol and the holy grail, ethanol. Although this does not replace fossil fuels with renewable sources of energy altogether, it could serve as an interim step towards creating a low-carbon future.

Storage

Carbon dioxide collected from power plants and industrial processes can be safely stored underground permanently using geologic formations. One common way of doing so involves injecting under pressure into porous rock formations with an impermeable cap rock. Ideal sites include depleted oil and gas reservoirs, unmineable coal areas, and deep saline aquifers.

CO2 remains stored underground for an indefinite period, like oil and natural gas do. While not yet an established technology, carbon capture could play an essential role in reaching net-zero emissions goals.

Cost-effective carbon capture and storage (CCUS) projects could significantly decrease energy demand while being cost effective; they require the support of governments and industry alike; several large-scale CCUS projects exist today including Norway’s Sleipner carbon capture site and UK’s Drax Power Station’s Zero Carbon Humber project (ZCH).