Frequently Asked Questions (FAQ)

Carbon capture and storage involves the processes of capturing carbon dioxide - typically from industrial processes or from burning fossil fuels – and transporting and storing it permanently deep underground in geological formations such as depleted oil and gas reservoirs.

CCS is counted as one of the most effective ways to decarbonise, making it a vital technology on the road to global net zero. According to the UN Intergovernmental Panel on Climate Change (IPCC), as the world transitions to a lower-carbon economy, global temperature changes cannot be kept at bay without capturing and storing CO2.

The technology behind CCS is well-proven and has been around for more than 40 years. It has traditionally been used for enhanced oil recovery (EOR). Studies have shown that CO2 can be safely stored underground in geological formations for thousands and even millions of years. The Nini reservoir has been tested by the Geological Survey of Denmark and Greenland (GEUS), and Greensand has been independently verified by DNV. Injection is continuously monitored within approved limits to protect the integrity of the reservoir.

Greensand stores CO₂ in a suited geological reservoir in the North Sea. From a geological perspective, the Greensand storage facilities in the North Sea (the Siri fairway) are extremely stable reservoirs. They have retained gas and oil for more than 10 million years, making them a very safe permanent storage site for CO2. The integrity of the Greensand Nini reservoir in the North Sea has been tested by the Geological Survey of Denmark and Greenland (GEUS), and Greensand Future has received safety approval from the world-leading independent verifier DNV.

Greensand is the EU's first full-scale CO₂ storage site in operation, located in the Danish North Sea. It forms the core of the EU's first full-scale CCS value chain: CO₂ captured at industrial emitters, transported to the CO₂ terminal at Port Esbjerg, shipped to the storage site with the EU's first dedicated CO₂ carrier vessel, Carbon Destroyer 1, and permanently stored in a geological reservoir roughly 1,800 metres beneath the seabed.

Greensand builds on a pilot project, completed in 2023, which was the first in the world to capture CO₂, transport it across a border and store it safely offshore. The pilot was supported by the Danish state through the Energy Technology Development and Demonstration Programme (EUDP).

The storage license holders behind Greensand are INEOS Energy Denmark, Harbour Energy and the Danish State Subsurface Resource Company Nordsøfonden.

Full-scale describes the transition from a pilot or demonstration to an operational CCS value chain. Greensand is the first operational CO₂ storage project in the EU with the ability to inject more than 100,000 tonnes of CO₂ annually - the threshold above which storage falls under the full permitting and monitoring regime of the EU CCS Directive. In its first commercial phase, Greensand stores up to approximately 400,000 tonnes annually, with the potential to expand significantly as more emitters become ready with capture.

Greensand offers permanent CO₂ storage as a service to companies that need access to storage as part of their own decarbonisation. We also offer actors along the CCS value chain - emitters, transporters and ports - the opportunity to partner with us and help scale the project as volumes of captured CO₂ increase.

Greensand provides safe and effective CO2 storage in a suited geological reservoir roughly 1,800 metres beneath the seabed, some 200 km off the Danish west coast. From a geological perspective, the Greensand storage facilities in the North Sea (the Siri fairway) are extremely stable reservoirs. They have retained gas and oil for more than 10 million years, making them a very safe permanent storage site for CO2. The integrity of the Greensand Future Nini reservoir in the North Sea has been tested by the Geological Survey of Denmark and Greenland (GEUS), and Greensand Future has received safety approval from the world-leading independent verifier DNV.

In its first commercial phase, Greensand Future, CO2 will come from Danish biomethane production with an aim to store 400.000 tonnes of biogenic CO2 per year – large volumes of which are readily available. In later phases, the CO2 will come from both biogenic and fossil sources.

We need to store as much CO2 as we can – as fast as we can. Right now, biogas production offers high volumes of CO2 that can be more easily captured compared to industrial fossil emission sources. While capture facilities at these sources mature into the needed scale, there is, in Europe alone, an estimated 21 mtpa biogenic CO2 from biogas plants that could be captured and stored rather than emitted. That is why we’re moving ahead now with an outlook to storing both biogenic and fossil CO2 as we develop the project.

Storing CO2 in the subsurface can have an impact on the marine environment in the unlikely case of a leakage. However, from a geological perspective, the collected Greensand storage facilities in the North Sea (the Siri fairway) are extremely stable reservoirs. They have retained gas and oil for more than 10 million years, making them a very safe permanent storage site for CO2. The integrity of the Greensand Future Nini reservoir in the North Sea has been tested by the Geological Survey of Denmark and Greenland (GEUS), and Greensand Future has received safety approval from the world-leading independent verifier DNV.

It’s not an either-or, we need to do both. According to IPCC, the International Energy Agency and the EU, there is no way to reach net zero emissions without capturing and storing CO2. While industries around the world are transitioning to lower-carbon business models, capturing and storing CO2 will be necessary to abate the emissions that can’t be avoided based on current knowledge and solutions.

Greensand is the first CO₂ storage site in the European Union to reach full-scale operation, defined as an operational storage project injecting more than 100,000 tonnes of CO₂ per year. This assessment is supported by the Global CCS Institute's Global Status of CCS report and CO2RE facility database, and by the European Commission's progress report on the EU-wide CO₂ injection capacity target. The full review is available in the factsheet.

Greensand provides effective CO2 storage, achieving a relative greenhouse gas avoidance of approx. 94%.

This means that 94% of the CO2 which would have otherwise been emitted will be stored. The remaining 6% is the GHG footprint attributed to operating the CCS value chain from liquefaction to transport and storage operations.

The 94% figure is based on an extensive Life Cycle Assessment (LCA), assuming the most conservative cases on energy consumption in the value chain, covering the processes from liquefaction of the CO2, transport and storage operations.

We expect efficacy to improve as new technologies and solutions reduce the carbon footprint of storage operations, further enhancing the project’s effectiveness in mitigating climate change.

No. Greensand is physical infrastructure that transports and permanently stores CO₂. A detailed life-cycle assessment using conservative assumptions shows approximately 94% greenhouse-gas avoidance across the full value chain. The remaining emissions are associated with activities such as liquefaction, transport and storage operations. This is a measurable result, not a promise.

The companies behind Greensand - the current storage license holders (IRIS) - are INEOS Energy Denmark, Harbour Energy and the Danish State Subsurface Resource Company Nordsøfonden.

Greensand works with several partners to ensure residual CO2 can be captured, transported to harbour sites, and sailed to the North Sea for permanent storage.

We are continuously exploring new partnership opportunities which can help strengthen the CCS value chain - from capture, transport and storage.

Reach out via greensand@ineos.com if you are interested in working with us.