The “Net Zero” scenarios are reliant on significant rollout of Carbon Capture, Utilization and Storage (CCUS) projects, as CCUS can tackle emissions from existing assets and at the same time provide a tool for addressing emissions from some of the most challenging sectors.
It can capture the CO₂ produced in the proposed large-scale hydrogen production via steam methane reforming; to enable firm, low-carbon power generation using Combined Cycle Gas Turbines (CCGT) and bioenergy; and in the decarbonization of CO₂ -emitting industrial processes. Technology wise, CCUS is when the CO₂ stored is derived from industrial point sources, and Direct Air Capture with Carbon Storage (DACCS), is when the CO₂ is captured from the ambient air.
Liquid carbon dioxide is carbon dioxide gas that is highly compressed and cooled to a liquid form.
Carbon dioxide exists as a liquid below the critical temperature of 31°C and above the triple point with a temperature of -56.6°C and 4.18 bar.
Unlike water, carbon dioxide cannot exist in the open air in liquid form. It must be held under pressure or refrigeration (or a combination of both) to remain in the liquid state.
Generally, CO₂ gas is transported, stored and handled in liquid form, either at a low temperature to limit tank cost thanks to lower pressure (-50°C, 7 bar) or a high temperature to limit Energy penalty in the liquefaction plant (-30°C, 15 bar).
CO₂ potential uses
Demand for liquid CO₂ in various industries has grown tremendously reflecting its diverse applications. It is widely used in the entertainment industry to achieve special effects; in the food industry for refrigeration, preservation, storage and softening; as a fire extinguisher due to its anti- flammable properties; and in oil recovery where the liquid is pumped into oil wells to recover more oil.
As part of carbon capture and storage (CCS), CO₂ can be trapped in geological media like oil and gas reservoirs for thousands to millions of years thereby mitigating CO2 release in the atmosphere.