CCS: Carbon capture and storage — making net zero possible

Carbon Capture and Storage (CCS) is a technology that can capture up to 90% of the carbon dioxide (CO₂) emissions produced from the use of fossil fuels in electricity generation and industrial processes, preventing the carbon dioxide from entering the atmosphere, and storing it permanently underground.

Carbon capture and storage (CCS) is one of the few technological solutions that can contribute to a significant reduction in emissions from industrial operations based on coal or gas power, keeping CO₂ out of the atmosphere that would otherwise worsen climate change.

Important contributions can also be made by applying CCS to the cement and steel industries, which represent 14 % of the world's CO₂ emissions.

Technology development within bioenergy with carbon capture and storage (BECCS) can make BECCS a negative emissions technology. By extracting bioenergy from biomass and capturing and storing the carbon, we can remove historic CO₂ emissions from the atmosphere.

CCS will be crucial for decarbonising industries such as cement and steel where production itself results in large CO₂ emissions, as well as other industries.

The International Energy Agency says that we need to store billions of tonnes of CO₂ every year to reach the UN climate goals. It’s also one of the key measures that the Intergovernmental Panel on Climate Change regards as necessary to keep global warming to 1.5 degrees Celsius. CCS is recognised as an important, proven technology for reducing greenhouse gas emissions around the world.

CCS involves three major steps; capturing CO₂ at the source, compressing it for transportation and then injecting it deep into a rock formation at a carefully selected and safe site, where it is permanently stored.

Capture: The separation of CO₂ from other gases produced at large industrial process facilities such as coal and natural-gas-fired power plants, steel mills, cement plants and refineries.

Transport: Once separated, the CO₂ is compressed and transported via pipelines, trucks, ships or other methods to a suitable site for geological storage.

Storage: CO₂ is injected into deep underground rock formations, usually at depths of one kilometre or more.

Energy from fossil fuels such as coal, oil and natural gas is released in the combustion (burning) and conversion process, which also results in the emission of CO₂ as a by-product. CO₂ is also a by-product of the production and purification of natural gas.

There are three basic types of CO₂ capture: pre-combustion, post-combustion and oxyfuel with post-combustion.

For more information, see Global CCS Institute.

Equinor has been developing technology to make this possible for more than 20 years, and we are a part of more than 40 research projects on carbon capture and storage.

The seabed off the coast of Norway is well suited to storing CO₂, and we can potentially store the equivalent of a 1000 years of Norwegian emissions under the North Sea.

Carbon dioxide, or CO₂, is naturally present in the earth’s atmosphere as a trace gas. As its name indicates, it consists of one part carbon and two parts oxygen. Its natural existence is in the form of a gas, which is inert and non-harmful to humans in low concentrations. Dry ice is carbon dioxide in its solid state.

Carbon dioxide is a by-product of respiration and exhaling in all aerobic organisms, from processes of decay of organic materials, and from the combustion of wood and other organic materials and fossil fuels such as coal, peat, oil and natural gas. Natural sources include volcanoes, hot springs and geysers.

Too much CO₂ is building up in our atmosphere from burning fossil fuels, and this has a warming effect that is changing the earth’s climate. This phenomenon is called the greenhouse effect.

Greenhouse gases are gases that contribute to climate change by trapping heat, like the glass in a greenhouse. The gases absorb solar energy and keep the heat close to Earth's surface, rather than letting it escape into space. This trapping of heat is known as the greenhouse effect. The most common and potent greenhouse gases are carbon dioxide, methane, nitrous oxide and certain industrial gases.

Extreme weather, food supply disruptions, and increased wildfires are effects of climate change caused by greenhouse gases. Today, climate change is the term scientists use to describe the complex shifts driven by greenhouse gas concentrations that are now affecting our planet’s weather and climate systems.

Virtually every sector of the global economy, from manufacturing to agriculture to transportation to power production, contributes greenhouse gases to the atmosphere, so all of them must evolve away from fossil fuels if we are to avoid the worst effects of climate change. Countries around the world acknowledged this reality with the Paris Climate Agreement of 2015.

The technologies for reducing greenhouse gas emissions include replacing fossil fuels with renewable sources, boosting energy efficiency, discouraging carbon emissions by putting a price on them, and capturing CO₂ from power plants and factories.

CCS is a proven technology that has been used commercially for four decades and has been used at commercial scale in several nations. Equinor has developed successful monitoring programs through 25 years of CCS experience, showing that CO₂ can be stored safely underneath the seabed. The Northern Lights project has further demonstrated the safety and efficiency of CCS technology.

Safely and permanently stored deep underground

Storing CO₂ utilizes the same mechanisms that have kept oil and natural gas trapped underground for millions of years. The CO₂ is stored at depths greater than 1 km. It is injected into saline formations suitable for storage or in depleted oil and gas reservoirs. Subsurface CO₂ storage requires two key elements: presence of a porous and permeable storage rock formation and a caprock that seals it. A suitable formation must form a ‘trap’ with the caprock. The structures that keep CO₂ in place are very similar to those in oil and gas fields, where hydrocarbons have remained stored for many million years.