Carbon Capture and Storage (CCS) technology captures CO2 produced at power plants and industrial facilities – such as steel production or burning fossil fuels to generate energy – before safely storing it underground within geological formations.
Petroleum coke is often used to refill depleted oil and gas reservoirs or saline aquifers.
Biological Sequestration
Plants and microbes naturally sequester carbon from the atmosphere into vegetation, soils, woody products and ocean waters to slow climate change. Biologically enhanced carbon capture and storage (BECCS) technologies offer another option than geologic carbon sequestration that involves injecting liquid CO2 underground.
Tax Cuts and Jobs Act of 2022 includes a provision that offers companies that capture and store carbon dioxide from fossil fuel-fired power plants a tax credit; this section, commonly referred to as 45Q, is meant to encourage large-scale CCS projects.
BECCS seeks to reduce fossil fuel reliance by lowering emissions, expanding renewable energy sources and slowing climate change. Unfortunately, leakage from terrestrial ecosystems, the effect on food production and economic models that fail to account for impacts on biodiversity or sustainable biosphere are among the concerns regarding BECCS implementation and must be resolved if BECCS benefits are maximized.
Carbonate Sequestration
Carbon dioxide taken out of the atmosphere through precombustion at power plants or natural gas processing plants or postcombustion at coal plants is captured and stored underground using geologic formations as a form of carbon capture and storage to help mitigate climate impacts related to fossil fuel use. This technology offers one means to do this effectively.
Carbon dioxide emissions can either be stored physically in porous rock formations, or chemically processed into stable mineral forms that will remain. Sometimes CO2 is even injected directly into oil-bearing rocks to aid with extracting crude oil.
Scientists are researching methods of making carbon sequestration more cost-efficient and environmentally sustainable. One approach involves combining it with bioenergy production through carbon capture, utilization and storage (CCUS), which would provide for an easier transition away from fossil fuels by using some emissions for energy production while keeping some long-term storage. Furthermore, CCUS may contribute towards attaining negative emissions technologies (NET), including direct air capture or DAC processes.
Soil Sequestration
Soil organic carbon (SOC) storage is an integral component of global carbon sequestration. Plants capture atmospheric CO2 through photosynthesis and transfer it via root exudates, litter fall, and dead plant material to the soil through root exudates, litter fall, and dead plant material. Over time these materials break down to form humus which stores carbon for centuries – agricultural practices like crop rotations, cover crops, reduced tillage techniques, organic amendments can accelerate this natural process further.
Raising SOC levels should have significant climate benefits, as well as improving soil health and water quality, lowering emissions of nitrous oxide, enhancing food security and providing relief to drought. But increasing SOC at scale presents unique challenges, such as better understanding of processes that contribute to its accumulation and degradation.
Concerns have also been expressed that SOC storage might eventually reach saturation point and prevent it from drawing down CO2, prompting carbon markets not to adopt this form of carbon storage.
Forest Sequestration
Forest sequestration involves planting, managing and maintaining forests to sequester more carbon than they release into the atmosphere. To do this effectively requires that more trees grow than die and that dead ones be quickly replaced; additionally it involves clearing away non-native plants which interfere with forest ecosystems and eliminating non-native species that interfere with them.
Wood burial offers tremendous potential for long-term carbon storage, with over 65 GtC of coarse woody material available to be buried across global forests (Eloka-Eboka and Inambao 2017). Burying organic matter under anaerobic conditions reduces its rate of decomposition.
Carbon capture and storage solutions can be costly and labor intensive, which may cause them to reduce motivation to reduce emissions or develop renewable energy sources if it costs less than burying wood for burial. Nonetheless, carbon capture should only ever be seen as one piece of a solution and not as a replacement.